Talk:Light-emitting diode/Archive 2

Who invented what

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:

• Title: Semiconductor Light Emitting Element
• Applicant: NTT
• Date of filing: 13th July 1987
• Inventors: Hidenao Tanaka, Takashi Matsuoka, Kunishige Oe

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)

Wonderful! This is the best contribution in this discussion so far! So, I'm changing the article to include this fact. — Sebastian 22:38, 22 January 2007 (UTC)

Thanks :-). Your edit is wrong however. The fact that Tanaka et al. (1987) is the earliest patent referred to by Nakamura in his 1993 patent doesn't mean that they were the first to develop a blue LED. Jacques Pankove made one as early as 1971, and the earliest (albeit unreliable) reports go back as far as 1861 (that's right, eighteen sixty-one). The blue LEDs you see everywhere these days largely owe their existence to Nakamura. I'd put this in the article myself but I don't have time right now. Maybe tomorrow. -- Sakurambo 桜ん坊 00:30, 23 January 2007 (UTC)

Sorry about that. I won't interfere with the article again until you edit it. I'm impressed again, and delighted about the Ernest Glitch gem you dug up! Weren't those people polymaths!? Do you know if anyone ever tried to reproduce his experiment?

Back to our topic: You already rewrote the title to contain two wildcard words; maybe we should add a third "who did what?" Maybe asking who invented it is the wrong question. It's sounds like asking who invented the transatlantic telephone cable. I wouldn't say Cyrus Field invented it - there have been phone cables and transatlantic telegraph cables before, so the idea was already there. The interesting question is who realized it, and it seems like all the names you mention should be in the article. — Sebastian 06:44, 23 January 2007 (UTC)

ZOMGZLOL! The "Ernest Glitch" article is a joke!!! I once had correspondence with the author of that website a few years ago in which I commended him for his absurdly elaborate ruse and worried that they were so good they would fool people into thinking things like the nitrogen laser were actually invented in the Victorian age. It seems I was right! :) :) --Deglr6328 08:45, 23 January 2007 (UTC)

Oops! :-D I'm glad you pointed that out. In that case I guess we should credit Jacques Pankove as being the first to make a blue LED. -- Sakurambo 桜ん坊 09:34, 23 January 2007 (UTC)

Well, then, tell your friend it's nice to see that there is still at least one polymath alive today! It is a well written piece. I don't think it's too harmful - or else I wouldn't believe in Wikipedia! — Sebastian 09:44, 23 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)

Intro

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)

Color lumens

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)

I believe you are talking about a color efficiency curve. It's better to understand a given amount energy used to determine the amount of lumen's produced for each color OR a given amount of lumens used to determine energy needs for each color. This way you relative comparison. Danpeddle 00:12, 3 October 2007 (UTC)

Typical LEDs are not bright or efficient

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)

The lighting industry doesn't use mcd, some LED manufactures do. We use a defined standard from the IESNA (Illuminating Engineering Society of North America). Here we define the efficiency in lumen's per watt and brightness in lumen's, but we can convert from candelas too (milli candelas are too small). The problem with the candela is it is based on the brightest (pin) point of the LED instead of light as a whole. We measure the LEDs (and other lighting) in a spheroid chamber where the total light output is collected and measured. This gives us a direct comparison between different forms of lighting, such as incandescent and fluorescent. Danpeddle 00:38, 3 October 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)

The glowing comparison to incandescents is misleading because it leaves open the question of how they compare with fluorescent, which is a more appropriate standard of comparison if you care about efficiency. It would be good to see a good sourced comparison. Dicklyon 22:28, 3 August 2007 (UTC)

The comparison to incandescent is normal, this is the light source people prefer based on the output color it typically generates. When comparing light sources, you must take into account the color that is cast by the light source. People today still feel the CFLs used for residential (incandescent replacements) are too white (caused by the blue white light). If you are comparing energy, then we use lumen's per watt and we can compare to any form of lighting, including the more efficient HID. However, the standard for measurement has come under fire lately. Some manufacturer's, seeing the fad for LED technology, have interpreted the test slightly different to allow their LED products to "achieve" a higher lumen's per watt. You will see companies making claims of 100 lumen's per watt, but this might be the result of measuring the light output when a momentary and destructive pulse is used on the LED. This, in turn, produces a brighter than normal light for less than a millisecond before the LED is destroyed. Currently, newer LEDs are about as efficient as fluorescent lighting. Unfortunately, they are also more expensive to produce for room lighting applications. Danpeddle 00:38, 3 October 2007 (UTC)

ballast buzz

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)

One of the two removed statements was "CFLs do still emit a quiet buzz, while LEDs are completely silent." This statement, containing no qualifiers, is flatly wrong. Most electronic CFL ballasts are as quiet as the control circuitry of any line-powered LED lamp. Atlant 01:18, 28 May 2007 (UTC)

In today's ballast, if a buzz is heard, it is because the core and bobbin of the transformers (we just say magnetics, they might also be inductors) are not glued or taped to prevent them from resonating. However, these days, ballast manufacturers are very aware of this and have very good process control. Today's ballasts are high frequency, running from approx. 40KHz to approx. 100KHz when dimmed. They are, essentially, a complicated switch-mode power supply. Ballasts of the past were large bulky inefficient transformers that operated on line frequency, 60Hz, or rectified line frequency, 120Hz and produced that audible hum, mostly from corona (around the insulating paper/mica). Danpeddle 00:02, 3 October 2007 (UTC)

white LED I-V curve

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).

Are variable color LEDs practical?

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)

please note that article talk pages are for discussion of the article, not general discussion. please see WP:FORUM. Anastrophe (talk) 06:23, 24 January 2008 (UTC)

Pronunciation

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)

it should go without saying that google search count results have virtually no probative value. i've been pronouncing it "el-ee-dee" for some forty years or so, and i've never had anyone ask "what are you talking about". i've never heard anyone refer to them as "leds". and... mirriam webster online corroborates. i'm going to cite and change it. Anastrophe (talk) 08:41, 4 January 2008 (UTC)

I work within the technical community in the United States and although I have always said "L-E-D(s)", you do hear it pronounced as "led(s)". To me, though, that's too ambiguous with the element lead as in "ROHS has forced us to use lead-free leds".

Atlant (talk) 14:02, 4 January 2008 (UTC)

That explains why I see "an LED" here and there. I believe I used to say "el-ee-dee" years ago before dealing with them on a regular basis, at some point I switched to "led" because it's quicker. Having forgotten this I was wondering what bizarre rule for acronyms was being applied to make people say "an led". As LEDs are rarely written as L.E.D. I believe it is an acronym like NASA, and I personally believe all instances in this article should be changed to "a LED" because reading "an led" is distracting to me, and also uncommon in my everyday readings of them (mostly dealing with LEDs used in torches). - 124.254.121.73 (talk) 17:10, 8 February 2008 (UTC)

There is nothing bizarre about "an el ee dee". The only question is whether it should it be "a led" or "an el ee dee". Personally I've never heard it pronounced "a led". Thunderbird2 (talk) 17:27, 8 February 2008 (UTC)

Calculator Picture

Is it just me or does this display look remarkably like Nixie Tubes?

not particularly, no. Anastrophe (talk) 08:10, 17 January 2008 (UTC)

Section layout

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. Yngvarr 18:44, 30 January 2008 (UTC)

fixed --Thorseth (talk) 07:26, 15 October 2008 (UTC)

What a mess

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)

A or B class

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)

History section

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)

fixed --Thorseth (talk) 07:27, 15 October 2008 (UTC)

Removed section from article

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".

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)

That DNA crap is unwikilike

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)

please see WP:IDONTLIKEIT. it's interesting, and describes genuine research. your justification for removal doesn't seem to be based on policy. Anastrophe (talk) 03:58, 20 April 2008 (UTC)

i should add that this research is very exciting. it could mean dramatic reduction in the cost of manufacture of LEDs. it belongs in the article. if you don't like how it's written: fix it. don't just delete sourced material. Anastrophe (talk) 04:01, 20 April 2008 (UTC)

Overly-technical lead?

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)

Should this get a mention?

This development. Kaiwhakahaere (talk) 20:17, 8 May 2008 (UTC)

This important thing should be added

http://en.wikipedia.org/wiki/Haitz's_Law (talk) June 20 2008 --Reachtokaushik (talk) 09:46, 20 June 2008 (UTC)

I put it in the history section and I am compiling a new graph. Available graphs are from around 2000 --Thorseth (talk) 12:40, 29 July 2008 (UTC)

Why is this article so long and unorganized?

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)

Take the shovel and go (and remove oled which isn't led). Mion (talk) 11:26, 4 July 2008 (UTC)

Proposal to put white LEDs in its own article

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)

We have Solid-state lighting and LED lamp if thats what you mean, please sign with ~~~~ at the end. Mion (talk) 14:32, 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)

True, i also think that the white led section belongs to LED, you can take whatever type of led to make a led lamp, including white leds. Mion (talk) 12:51, 5 July 2008 (UTC)

White is not the only phosphor-based LED

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)

"LED panels" should be put in its own article

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)

Materials and colors

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?

Color	Wavelength (nm)	Voltage (V)	Semi-conductur Material
Infrared	λ > 760	ΔV < 1,63	Aluminium gallium arsenide (AlGaAs)
Red	610 < λ < 760	1,63 < ΔV < 2,03	Aluminium gallium arsenide (AlGaAs) Gallium arsenide phosphide (GaAsP) Aluminium gallium indium phosphide (AlGaInP)
Orange	590 < λ < 610	2,03 < ΔV < 2,10	Gallium arsenide phosphide (GaAsP) Aluminium gallium indium phosphide (AlGaInP)
Yellow	570 < λ < 590	2,10 < ΔV < 2,18	Gallium arsenide phosphide (GaAsP) Aluminium gallium indium phosphide (AlGaInP)
Green	500 < λ < 570	2,18 < ΔV < 2,48	Gallium(III) nitride (GaN) Gallium(III) phosphide (GaP) Aluminium gallium indium phosphide (AlGaInP) Aluminium gallium phosphide (AlGaP)
Blue	450 < λ < 500	2,48 < ΔV < 2,76	Zinc selenide (ZnSe) Indium gallium nitride (InGaN) Indium gallium nitride (InGaN) Silicon carbide (SiC) as substrate Silicon (Si) as substrate — (under development)
Violet	400 < λ < 450	2,76 < ΔV < 3,1	Indium gallium nitride (InGaN)
Ultraviolet	λ < 400	ΔV > 3,1	diamant (C) Aluminium nitride (AlN) Aluminium gallium nitride (AlGaN) Aluminium gallium indium nitride (AlGaInN) — (down to 210 nm)
White	Broad spectrum	ΔV = 3,5	Blue/UV diode with phosphor

--Thorseth (talk) 11:32, 14 August 2008 (UTC)

Updated the table with information from the materials section--Thorseth (talk) 08:30, 15 August 2008 (UTC)

updated two links, missing a more specific link to Δ (delta has many uses) , support for the table. Mion (talk) 11:42, 15 August 2008 (UTC)

Δ = Modern Greek ? Mion (talk) 15:53, 18 August 2008 (UTC)

It is my understanding that Δ can also denote an interval of possible values, but i have been unable to find a good reference for this, but perhaps its use here is not entirely correct as Δ would be the interval and not the specific range. What do you think? --Thorseth (talk) 08:03, 19 August 2008 (UTC)

Well, if you mean a specific range ΔV = 0 < 2,48 V, its correct, but its not my field, so any suggestion is better than mine. Mion (talk) 21:58, 19 August 2008 (UTC)

Color VS. Operating Temperature

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)

The effect you describe is important for understanding the basic physics of LEDs but still comparatively small for normal operation temperatures. I think it could be mentioned, but should perhaps be elaborated on in an in-depth article on LED physics.--Thorseth (talk) 07:01, 1 September 2008 (UTC)

Latest Discoveries

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 think it might be included under experimental technologies, but on the other hand there are many scientific papers on LED every month. We can't reference all of them especially since this is a overview article.--Thorseth (talk) 07:24, 1 September 2008 (UTC)

Green/Pure Green distinction

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)

Putting this here because as of now it's little more than random trivia.

Research on DNA

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].

Laptops with LED Screens

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:

Netbooks probably use LED on higher-end models, and maybe fluorescent to cut costs.

LED-lit LCD screens use white LEDs.

I think the eye hazard of LED backlighting is minimal, and about the same as a standard fluorescent backlight. Ginbot86 (talk) 03:28, 2 December 2008 (UTC)

Most notebook computers (if not all) use LCD technology, which is liquid crystal. These do not produce any light, but selectively block light passing through from behind. The backlighting has been mostly provided by fluorescent tubes, but more recently, white LEDs have been used for this purpose. I may be unaware if there are some recent developments using LEDs directly for a computer display.Landroo (talk) 13:20, 9 May 2009 (UTC)

Christmas lights ...

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)

I agree. But there already a lot in Christmas lighting technology so perhaps just merge with and link to that.Ccrrccrr (talk) 22:00, 3 January 2009 (UTC)

I hadn't noticed that article. I think you are right. --Thorseth (talk) 09:52, 4 January 2009 (UTC)

Overly confusing and technical Lead.

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)

Well, LEDs are pretty complex devices to begin with. The problem as I see it is that the lead is either going to be very technical or very long. I have made a suggestion below that I would like you to comment on:

A light-emitting-diode (LED) /ˌɛliːˈdiː/, 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 last sentence might be expendable, but besides that I don't think I can make the lead both easier and shorter without removing essential information. --Thorseth (talk) 09:30, 5 January 2009 (UTC)

"is a semiconductor diode, that emits" or "light-emitting (semiconductor) diode" would probably work better and is easy to remember from the mnemonic "LED". 'Diodes' can also mean vacuum tubes with just 2 plates. I highly doubt anyone makes any kind of LED but semiconductors, but I put in parentheses to point out that it is implied. JWhiteheadcc (talk) 18:42, 21 February 2010 (UTC)

copyright problems

Resolved

 – Copyvios removed

The user User_talk:WikiEditorContributor has copy-pasted material from industri news web sites

please compare

ledjournal

wiki edit

and

ledinsider

wiki edit

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)

Removed section: Christmas lights

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-kiloohm 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.

There is already a rather extensive at Christmas_lighting_technology#LEDs so I think it would be safe to remove it.--Thorseth (talk) 13:57, 15 January 2009 (UTC)

Cree diode WP:OR WP:RS delete?

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. 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)

Thanks for removing the portions that were clearly OR. The 350 mA number is not OR, but was removed. That's OK with me, but if someone think's it's valuable you should feel free to add it back in.

I'm in favor of keeping the rest. Taking the issues one-by-one:

First is this luminous efficacy of radiation (LER) or luminous efficacy of a source (LES)? If it were LER, it would be lower than the products they have on the market already which are right near the 100 lm/W LES point, and about 250 to 300 lm/W LER. So it wouldn't be newsworthy. It is not, however, true wallplug efficacy, which would include ballast (drive circuit) losses, as it is a report on the performance of an LED, not an LED fixture or screw-in incandescent replacement which would include ballast losses. The LED can't be plugged into the wall, and thus wallplug efficacy is not the proper term. LES is the terminology established by international convention for what is measured here. We also know that LEDs of the type Cree makes have about 3 to 3.3 V voltage drop, so although the OR calculation of voltage doesn't belong in the article, one can reassure oneself that the 161 lm/W LER is consistent with expected voltages.

As far as the use of a press release, I note that 1) Cree is a pretty reputable company, and for example works closely with NIST on measurement of a lot of their devices. 2) Aside from being self-serving, this meets all the conditions mentioned above, and 3) The article says "Cree issued a press release..." rather than just stating the 161 lm/W as fact.

I do have a concern about quoting this value in a way that leads people to think it corresponds directly to what would be achieved in a fixture--an LED in a typical fixture is operating well above room temperature and that can degrade efficiency greatly. And, though this can be a small effect, drive circuit losses also need to be factored in.Ccrrccrr (talk) 12:44, 13 January 2009 (UTC)

Operating Room Surgical LED lights

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)

Its certanly a very long section (in an already long article) for such a niche application. If it was forked to its own article it would likely be speedy'd as advertising. At least trim to much shorter (i.e. a bullet point, as elsewhere in the article) and remove all pov/adspeak. Wouldn't oppose complete removal. StealthFox 14:14, 15 January 2009 (UTC)

Peer review...

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)

Here is the link to the review Wikipedia:Peer_review/Light-emitting_diode/archive1 --Thorseth (talk) 13:42, 5 February 2009 (UTC)

Lens

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)

New lead

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.

A light-emitting diode is an light source that emit light when a electrical current is applied to it. Discovered in the early 20. century the technology has been greatly developed and continues to advance through research and development. From early indicator lights that were very dim and only had one available color, to today's devises that emit visible, ultraviolet or infra red light, with very high brightness.

The technology behind LED is based on semiconductor technology, also used in modern computers. In the semiconductor diode, electrons are brought from a state of high energy to a low energy state and the energy difference is emitted in the form of light, this effect is called electroluminescence. Specific colors are associated with specialized materials that are constructed to have an energy gap corresponding to light with particular wavelength/color.

LEDs have many advantages to traditional light sources, such as: Low energy consumption, longer lifetime, robustness, small form factor. However they still remain relatively expensive, and have some characteristics that differentiate them from traditional light sources, such as need for current- and heat management.

These advantages have cause LEDs to be used in many new applications where no traditional light source could be used, as well as traditional applications where especially the low energy consumption is appreciated. Despite high price and the need for specialized design LEDs are being used more and more widely.

What do you think? --Thorseth (talk) 10:23, 13 February 2009 (UTC)

Localize

Resolved

 – Corrected in the article

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)

Custom designs?

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)

Well if you have a better term, it is very welcome. However I would say they are custom in the way that they are made for a more specific purpose. I think it´s a stretch calling them applications, when compared with the list of "real world" applications - that list actual uses of the technology and not specially tailored devices. Anyway I bunched them together because I don´t think the require a subsection each. --Thorseth (talk) 11:51, 22 February 2009 (UTC)

If you admit not custom designs, I would suggest it to be "Variation for specific applications".--Namazu-tron (talk) 23:19, 22 February 2009 (UTC)

Its a bit long for a heading but I guess it's OK.--Thorseth (talk) 08:45, 23 February 2009 (UTC)

Thank you for accepting my suggestion. More variation types may be appear in future.--Namazu-tron (talk) 19:43, 23 February 2009 (UTC)

Inventor

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)

Holonyak is probably the best choice. Round and Loslev's devices never made it outside the lab. This article is about the electronic component, so it's probably better to talk about the inventor of the practical component than the early pioneers of electroluminescence experiments. Papa November (talk) 11:20, 23 February 2009 (UTC)

Ok, I agree. Nice work on the article by the way--Thorseth (talk) 11:35, 23 February 2009 (UTC)

Thanks, but you've done far more than I have :) I think we can get this through WP:GAN with a little work, if you're interested. I think we need to beef up the references substantially, complete the copyediting and convert the applications section to prose. Papa November (talk) 11:44, 23 February 2009 (UTC)

Grammer Mistake?

light emit/light emits (first section) —Preceding unsigned comment added by 67.233.167.196 (talk) 14:39, 15 February 2009 (UTC)

An LED or a LED

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)

The normal spoken form is "an LED". Papa November (talk) 14:00, 24 February 2009 (UTC)

Can you please explain why an article should be used here? Komap (talk) 21:10, 25 February 2009 (UTC)

It is determined by spoken English rather than written English. "a" is used when the following word starts with a consonant sound ("a bottle"), while "an" is used when the following word starts with a vowel sound ("an apple")

"LED" starts with a vowel sound in spoken English ("An ell ee dee"). Papa November (talk) 10:24, 26 February 2009 (UTC)

Papa November = wrong. I'd suggest you stop with incorrect comments. If you cannot grasp the english language, then just stop. —Preceding unsigned comment added by 115.70.80.179 (talk) 23:57, 5 January 2011 (UTC)

The comment above is an idiot, of course it is 'an LED' if the letters are pronounced individually for the reasons Papa November wrote. If you were ignorant enough to pronounce it led as in Led Zeppelin then by all means write and pronounce it as 'a led' and sound like a moron. — Preceding unsigned comment added by 79.70.105.76 (talk) 20:51, 21 June 2011 (UTC)

An absurd number of articles involving light-emitting diodes

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:

• Light-emitting diode (currently 64,008 bytes, so there's little or no scope for merging articles into it; perhaps some material could be split off into the new articles I suggest below)
• Organic light-emitting diode (deserves its own article)
• LED circuit (currently not very useful, but perhaps could be a destination for "using LEDs in circuits" information)
• Electrical polarity of LEDs, a convention for how LED polarity is indicated (merge to LED circuit?)
• LED power sources (merge to LED circuit?)
• Thermal management of high power LED (merge to LED circuit?)
• LED as light sensor (merge to LED circuit?)
• List of LED failure modes (merge into new LED physics article?)
• Light extraction in LEDs (merge into new LED physics article?)
• Solid-state lighting (lighting using various types of LEDs; move to LED lighting?)
• LED lamp (same as LED lighting?)
• LED stage lighting (another aspect of LED lighting?)
• LED anti-collision light (merge into new LED beacons article?)
• Motorcycle LED Lighting (merge into new LED beacons article?)
• LED anchor light (merge into new LED beacons article?)
• LED Art (deserves its own article)
• Blinky (novelty) (merge into LED Art)
• LED Throwie (merge into LED Art)
• LED Incapacitator (move to LED products?)
• Individually Modulated LED (move to LED products?)
• LED printer (move to LED products?)
• DPL Therapy (a single manufacturer's IMHO dubious medical technology; move to LED products or delete?)
• LED display, a video display that uses LEDs (does this need an article? or move to LED products?)

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)

Merge away. some of these seem unlikely entries in the search box anyway and many are orphaned. --Wtshymanski (talk) 23:11, 2 March 2009 (UTC)

I broadly agree with the merge/delete principle, but let's think about it carefully. Firstly, let's consider why this article is too long. The largest sections are about types of LED (including various materials, colours etc) and applications. For the Capacitor articles, I suggested covering the subject into four main article: Capacitance (about the physics), Capacitor (a general summary of the man-made component), Applications of capacitors and Types of capacitor. I think we could cover the LED articles with broadly the same approach:

1. Light-emitting diode (a general summary of the man-made component)
   • History of LEDs
   • Brief summary of the physics (electroluminescence and p-n junctions)
   • Circuit theory: rectification, power sources
   • Non-ideal effects and typical "data-sheet parameters": efficiency, failure modes
   • Summary of different types/colours/materials (main article: Types of LED)
   • Overview of applications (main article: Applications of LEDs)
2. Electroluminescence and p-n junction (much more detail about the physics)
3. Applications of LEDs: Can split into multiple articles if necessary
4. Types of LED: May be better as a list

I think we can summarise all of the articles you listed into these major subject areas. A few applications such as LED lighting may be large enough subjects to warrant their own article while others like LED art and LED products are better kept as part of Applications of LEDs. Things like LED physics are already covered elsewhere. Papa November (talk) 00:36, 3 March 2009 (UTC)

I would Strongly Oppose merging this article LED stage lighting into LED lighting. Just as we have an article for Lighting and Stage lighting and an article for Lighting fixture and Stage lighting instrument. The article may not be that useful for someone researching LEDs but for someone researching their use in stage lighting it would be. -JWGreen (talk) 05:54, 3 March 2009 (UTC)

I'm not sure exactly what you are opposing. No one suggested merging Light-emitting diode into LED lighting or vice versa. Papa November (talk) 09:15, 3 March 2009 (UTC)

Sorry, I figured it out... you oppose merging LED stage lighting into LED lighting. Well, if it's a big enough subject in its own right then I agree. Papa November (talk) 09:46, 3 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:

1. Light-emitting diode: the primary article, with references to other articles in the LED family; would include packaging and material from current Electrical polarity of LEDs
2. Organic light-emitting diode: keep this separate since there seems to be a lot of good material here, although I haven't looked it over for redundancy
3. LED circuit: the circuitry surrounding an LED (including material from LED power sources, Thermal management of high power LED, and LED as light sensor)
4. LED physics: the internals of how LEDs function; although I'd consider presenting the material in Electroluminescence and p-n junction it doesn't make sense to me at first glance
5. LED lighting: using LEDs to cast light on other objects (and I don't see why LED stage lighting shouldn't be a category within this, especially as it's only about 3kB)
6. LED beacon: using LEDs to call attention to an object (e.g. airplanes, buoys)
7. LED display: using LEDs to deliver information (e.g. images, video, text) (yes, there already is an LED display article, but it only covers video displays, which is overly specific given the broad title)
8. LED art: self-explanatory (and I think deserving of a separate article)
9. LED products: random LED-based products that I'm not sure fit elsewhere (e.g. LED Incapacitator, Individually Modulated LED, LED printer, DPL Therapy)

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)

Regarding LED stage lighting, stage lighting is a much different craft than household or commercial lighting. Within stage lighting, we have separate articles for each type of lighting instrument used for stage lighting, and LED stage lighting instruments are one type. While the article may not provide much information about LEDs, the article provides information related to their use in stage lighting. Just because it would fit within another article doesn't mean it should. -JWGreen (talk) 00:24, 4 March 2009 (UTC)

But, the benefits of LED stage lighting seem to be the same as any LED lighting: lower power (and thus simpler power supply), lower heat, rapidly changeable, color control. (I'm not going to force the issue, but it still doesn't make a lot of sense to me. Perhaps if the article had one of those enormous templates at the bottom that places it in a structure of articles...) -- Dan Griscom (talk) 03:07, 4 March 2009 (UTC)

The article isn't so much about the benefits of LED stage lighting instruments, but about the practical use of the instruments. -JWGreen (talk) 03:37, 4 March 2009 (UTC)

Well, we have one editor for merging LED stage lighting, one against. Unless someone else chimes in, we should stick with the status quo. -- Dan Griscom (talk) 12:39, 4 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:

1. Light-emitting diode: the primary article, with references to other articles in the LED family; would include packaging and material from current Electrical polarity of LEDs
2. Organic light-emitting diode: keep this separate since there seems to be a lot of good material here, although I haven't looked it over for redundancy
3. LED circuit: the circuitry surrounding an LED (including material from LED power sources, Thermal management of high power LED, and LED as light sensor)
4. LED physics: the internals of how LEDs function (including List of LED failure modes and Light extraction in LEDs)
5. LED lighting: using LEDs to cast light on other objects (including material from Solid-state lighting and LED lamp)
6. LED stage lighting (keep as-is)
7. LED beacon: using LEDs to call attention to an object (including material from LED anti-collision light, LED anchor light and Motorcycle LED Lighting)
8. LED display: using LEDs to deliver information (e.g. status, images, video, text) (yes, there already is an LED display article, but it only covers video displays, which is overly specific given the broad title)
9. LED art: self-explanatory (including material from Blinky (novelty) and LED Throwie)
10. LED products: random LED-based products that I'm not sure fit elsewhere (e.g. LED Incapacitator, Individually Modulated LED, LED printer, DPL Therapy)

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)

don't merge

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)

Oops, made that first comment before seeing all of the thread. I like the latest list, and I agree with stage lighting being separate.

I think the main article will need to do a good job of branching people out to the correct other article earlier. The article started out as an article about an electronic component, but with people now coming to it wanting to know about light sources, we should send them to the article about light sources before they get discouraged reading about an electronic component.Ccrrccrr (talk) 04:52, 19 June 2009 (UTC)

LED design and control

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)

The link you provide require some sort of login screen which makes me wonder if the diagrams you talk about are not copyrighted, and as such unusable in Wikipedia.

I think you must have missed Led#Colors and materials, a lot of materials and colors are listed here.

There are a lot of LED drivers out there, this one would have to be very special to get a mention here.

You are welcome to make changes that you think are appropriate, but keep in mind that Wikipedia has strict policies on copyright, notability etc, and that these may sometimes be enforced a bit heavy handed. Posting here is a good start.--Thorseth (talk) 11:15, 6 March 2009 (UTC)

I agree with User:Thorseth's points above. Just a further addition: all diagrams are copyrighted, even if the website is readily accessible - there needs to be an explicit message stating that the images are freely licensed. Papa November (talk) 11:42, 6 March 2009 (UTC)

Strobing LED car backlights.jpg removed

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)

Thank you, I removed the picture because I thought it was unclear what it actually depicted. Yes strobed LEDs can be seen in this way, but I think its more a mistake than anything else, strobing should be done at much higher frequencies (unnoticeable), imagine being a truck driver sitting in strobed red light all night. The image might be better suited for Automotive lighting#Light emitting diodes (LED) where I find it much more pertinent --Thorseth (talk) 14:14, 19 March 2009 (UTC)

NPN bipolar transistor will emit violet light - Off Topic?

"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)

I think it's close enough to on-topic--it's a reverse-biased diode in that case (the other junction isn't involved). But it sure sounds like OR to me, and as much as I'm delighted to read about it, it belongs on a chat board somewhere not in WP.Ccrrccrr (talk) 04:44, 19 June 2009 (UTC)

Manufacturing data

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)

Waste

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)

Could you back that up with a reference? How much do the 50 or 100 incandescent bulbs weigh compared to the LED lamp? Just *how much * less energy-intensive is glass than aluminum, if at all? Recall that aluminum recycles like a dream - can bulbs even be made from recycled glass? Facts are nearly essential to an encyclopedia. --Wtshymanski (talk) 03:57, 6 August 2009 (UTC)

I could easily look up energy intensity of glass and Al, but if I were to go weighing LED screw-in replacements and incandescents, I think that would be OR. So I think we are stuck not having any statement about it in the article until someone finds a reliable source. Wish I could help more. --Ccrrccrr (talk) 14:43, 6 August 2009 (UTC)