Slashdot Mirror

"That sounds like a load of utter bullshit."

https://www.photonics.com/Arti...
https://www.eenewseurope.com/n...
https://www.ledsmagazine.com/a...

I guess your "confirmation bias" switch is set to the on position?

That or you did not even bother to check or just assumed that none existed, which is typical of an ignorant person.

If facts will not change your mind how do you expect to become informed? the LED component itself is not the only thing that can fail.

I have personally had 25% of my LED lights fail far too soon, from 4 different mfg's in 3 locations, but my information is purely anecdotal, just like yours is.

No, California classifies any light with an Edison socket as low-efficiency, not matter what bulb you put in. They're banned in kitchens completely, and only allowable if you put in a dimmer switch that will damage some high-efficiency lights that would otherwise work in an Edison socket.

You keep saying this, but I cannot find anything to support that idea. This mentions only efficiency requirements, not socket type:

http://www.huffingtonpost.com/...

As does this: http://www.ledsmagazine.com/ar...

If in fact you can provide me with a reference to this supposed ban on kitchen edison sockets I would be interested to see it.

Oh I spoke too soon - I found some. This is a reference that seems to support your statement: http://www.title24express.com/...

"According to the Title 24 energy standards a high efficacy luminaire contains only high efficacy lamps or high efficacy LED lighting, and must not contain a socket which allows any low efficacy lighting system to be used. For example, any luminaire containing a medium screw base socket is classified as low efficacy, regardless of the type of lamp installed into that socket. Typically, high efficacy luminaires contain pin-based sockets, like compact fluorescent or linear fluorescent lamp sockets, though other socket types such as screw sockets specifically rated only for high intensity discharge lamps (like metal halide lamps) light emitting diode (LED) luminaires (dedicated LED lighting fixtures that cannot use incandescent or any other type of lighting technology) may also qualify as high efficacy."

It does seem like a bit of almost pointless legislation since low efficiency bulbs can be found for various pin-based socket systems.

Any reason they couldn't add these LED sterilizers, either to the air filtration system, or to the lighting system of the station? Maybe take a room offline for 24 hours every week or so to sterilize.

http://www.ledsmagazine.com/ug...

Links, please? Last I checked, UV-C emitting diodes were essentially experimental items, with output power below 1mW, and sky-high prices. Feel free to ridicule me mercilessly if I'm wrong, but please post links; I'm a lot more interested in learning about UV-C emitters than in defending my hypothetical reputation.

This page crows about UV-C LEDs, but is conspicuously silent about output power (beyond calling it "stable"), availability, or price.

This page claims 5-10mW per device, adding that "limited release engineering samples are available today." The datasheet is mum on device lifespan.

This looks more promising -- 10mW per device, 10,000 hour life -- but where are the products, and where are the prices?

Obviously, I could be missing some products that are already shipping. But if you actually have a bank of UV-C LEDs that's been putting out enough power to kill algae in your aquarium for the last five years, it looks like a lot of electronics and physics journals would be interested in hearing from you. And so, as I said, would I.

"Note that commonly available UV emitters (including UV lasers and LEDs and the quantum dots mentioned in the article) are so far out of the effective range to be completely ineffective."

Bullshit.

http://www.hexatechinc.com/uv-...

http://www.cisuvc.com/

http://www.ledsmagazine.com/ug...

I was playing with UV-C LEDs from Nichia years ago that worked just fine for sterilizing water. It's still in use keeping algae from growing in my aquarium.

Should the inventor of Blue LED even have gotten one? Considering the health risks to his invention...

http://www.ledsmagazine.com/ar...

"including one that says the blue-light component in white LEDs causes toxic stress to the retina."

"LEDs on the other hand have to convert the energy which requires circuitry hidden in them, disperse the heat involved with that, and then fire a LED shrouded in a reflector in such a way that you don't over power it and start fighting droop. It is immensely more complicated and requires a lot more to get operating then regular bulbs."

Totally wrong. We've got LEDs that work directly off of AC connections, self-regulate, and have practically zero additional circuitry.

http://ledsmagazine.com/features/3/5/2

In the meantime, be quiet. You're simply speaking without having any real clue.

In 2005, the Commonwealth of Kentucky replaced all 77,000 traffic lights in the entire state with LEDs over the course of about a month. Citation

a large inrush current (such as a motor)

LED Lighting and the divers that run them have a significantly larger inrush current than incandescent lighting ( http://ledsmagazine.com/features/9/3/7/EcosystemFig3 ). I'd be more concerned about that than a motor.

This "feature" of LED lighting was not something that was initially taken into account.

Check out this article that describes thermal runaway in parallel strings of series-connected LEDs due to Vf variation.

Suppose you have designed a 2 LED series circuit (Vf = 3V, If = 100mA) to run off 12VDC. You'd use a 60 Ohm resistor [ (Vcc - Vftotal) / If ]. Now assume that one of the LEDs has a Vf of 2V instead of 3V. The current becomes [ (Vcc - Vftotal) / 60 ], which is now 116.67 mA. Not good.

Since LEDs act as any other diode, the current rises very quickly once Vf is exceeded.

LED lamps will almost certainly have the same thermal failure problems for precisely the same reason. Electronic circuits are simply not designed to operate at such high temperatures, and when you try to use them that way, they will fail much, much sooner than they ordinarily would.

Not to burst your bubble, but you know that LEDs are made from silicon and other semiconductors jut like MOSFETS and CPU's, right? They run at _very_ high temperatures - the max junction temperature of many MOSFETS can run as high as 175-200C!

This figure shows a Vfwd vs temp graph of an LED junction temp of 120C.

Unfortunately the article doesn't mention how they're growing the GaN on silicon. If you can't grow it fast, and very uniform, then this won't be of use for LEDs.

A quick Google for "GaN on silicon" yields this cautionary article.

Forward voltage to current is non-linear. It is exponential.You can approximate it linearly if you want, but you'll get error.
Fine, those charts show current handling, not luminous efficacy.
Try this chart for size:
http://www.ledsmagazine.com/features/4/8/1/MarlFig4

Still not convinced?
http://www.ledsmagazine.com/features/4/8/1
"The light output from an LED light source decreases with increasing LED die junction temperature. Higher LED die junction temperatures, resulting from increased power dissipation or changes in ambient temperature, can have a significant effect on light output."

If you want even more:
http://optodatabook.liteon.com/DataBookFiles/8426/LTST-C190CKT.pdf
Look at figure 5 on page 6. This is live charts for a real part used in real electronics.

Forward voltage to current is non-linear. It is exponential.You can approximate it linearly if you want, but you'll get error.
Fine, those charts show current handling, not luminous efficacy.
Try this chart for size:
http://www.ledsmagazine.com/features/4/8/1/MarlFig4

Still not convinced?
http://www.ledsmagazine.com/features/4/8/1
"The light output from an LED light source decreases with increasing LED die junction temperature. Higher LED die junction temperatures, resulting from increased power dissipation or changes in ambient temperature, can have a significant effect on light output."

If you want even more:
http://optodatabook.liteon.com/DataBookFiles/8426/LTST-C190CKT.pdf
Look at figure 5 on page 6. This is live charts for a real part used in real electronics.

I think she'll go away once infringement has been settled. Having settled with Philips and Toyoda this doesn't look much like a troll to me.

One of the reasons commercial LED color mixing units are so expensive in the US is patents. Color Kinetics (now owned by Philips) have a large set of patents covering color mixing with LED's using PWM which this project appears to be doing. Most US manufacturers have been forced to license this from Color Kinetics. Attempts to overturn the patent have failed e.g. http://www.ledsmagazine.com/news/3/12/3

Don't try using Pulse Amplitude Modulation for color mixing either - that's also been patented!

Sadly, yes.
http://www.ledsmagazine.com/features/1/12/8

An LED company patented RGB color mixing and Pulse Width Modulation for LEDs. Both of which have been common technologies for years. But the patents have continued to hold up, and surprise surprise, it's slowed the industry and hampered progress.

Shuji Nakamura got boned by his employer Nichia, and it's got to feel sweet for him that he's getting recognized for his work anyway.

"The court actually valued Nakamura's contribution to the company at 60.4 billion yen, based on Nichia's sales and the revenue that it might theoretically have received from licensing a key patent relating to the epitaxial growth of LED material."

http://www.ledsmagazine.com/articles/news/2/1/5/1