This is hack a public radio episode 3,192 for Tuesday the 27th of October 2020.
Today's show is entitled, A Light bulb Moment. Part 3. It is hosted by Mr. X.
and is about 13 minutes long and carries an explicit flag. The summary is the LED Revolution.
This episode of HBR is brought to you by AnanasToast.com. Get 15% discount on all shared hosting with the
offer code HBR15 that's HBR15. Better web hosting that's Aniston Fair at AnanasToast.com.
Hello and welcome hacker public radio audience. My name is Mr. X and welcome to this podcast.
As usual I like to start by thanking people at HBR for making this service available to us all.
HBR is an invaluable service on these intertrips. HBR is a committed podcast provided by the
community for the community. That means you can contribute to why you pick up a microphone
and record something and send it in. Sure you could do that, can you? If I can do it so can you
and if we all did it it would have more shows they would know to do with. Okay so this is part 3 of my
light bulb moment series and they will follow on from where we left off. This one is going to
cover the development of the LED. This chief LED Revolution is both long and complex but I'll do my
best to cover it. Please forgive me if I mispronounced some of the materials and processes as I'm
not a lighting expert. As I stated right back at the beginning of this series, most of the following
excerpts are from Wikipedia. The LED or lighting meeting diode first appeared as a practical electronic
component in 1962. The earliest LED emitted low intensity infrared light. infrared LEDs are used
in remote control circuits such as used with a wide variety of consumer electronics. The first
visible light LEDs were of low intensity and limited to red. Modern LEDs are available across
the visible ultraviolet and infrared wavelengths with high light output. A great deal of development
and the Feynman was required to get to this point. The first commercial visible wavelength
LEDs were commonly used as replacements for incandescent and neon indicator lamps and then
certain segment displays. First an expensive equipment such as laboratory and electronic test
equipment then later in such appliances as calculators, TVs, radios and telephones as well as
watches. Until 1968, a visible and infrared LEDs were extremely costly in the order of
200 US dollars per unit and so had little practical use. The breakthrough came around in 1968
when one santo was the first organization to mass produce visible LEDs. These were red LEDs
suitable for indicators. In February 1969, Hewlett Packard introduced the HP Model 508-7000
numeric indicator. The first LED device to use integrated circuit technology. It was the first
intelligent LED display and was a revolution in digital display technology. Replacing the next
YouTube and becoming the basis for later LED displays. The early red LEDs were bright enough only
for use as indicators as light output was not enough to eliminate an area. Redoids and calculators
were so small the plastic lenses were built over each digit to make them legible.
Yes, I remember having these LED calculators that you could barely see the digits and
a very early digital watch. The summary is a push to button and it comes on briefly. You could
see hours, minute, seconds, month, day, day, day, night sort of stuff. It used so much power that
you know it only came on briefly when you pushed the button. Yes I can remember those.
You'll see what an old fart I am. Later other colors became a widely available and appeared
in appliances and equipment. The first blue violet LED using magnesium-doped
gallium nitrate was made at Stanford University in 1962 by Herb, Miraska and Wolley Rains.
In 1973, Pankov and Ed Miller demonstrated the first blue electric luminescence from Zenk-doped
gallium nitrate. Though the subsequent device, Pankov and Miller built the first gallium nitrate
light emitting diode, emitting a green light. Today, magnesium-doping of gallium nitrate remains
a basis for all commercial blue LEDs and laser diodes. In the early 1970s, these devices were
to them for practical use and research into gallium nitrate devices slowed. In 1993, high brightness
blue LEDs were demonstrated by Suji Nakamara of Nietzsche Corporation using a gallium nitrate growth
process. In parallel, I Sama Akasaki and Hiroshi Amano and Nangai was working on developing
the important gallium nitrate deposition on surface substrates on the demonstration of p-type
doping of gallium nitrate. This new development revolutionized LED lighting, making hyper-blue
light sources practical, leading to the development of technologies like blue ray. As he
Wikipedia has its square bracket citation needed here. In 1995 Alberto Barberi at the Cardiff University
laboratory Great Britain investigated the efficiency and reliability of high brightness LEDs
and demonstrated a transparent contact LED using indium tin oxide. I'm not even trying
guess all this. It's a capital A small L capital G small A capital I small N capital B and there's
a forward slash capital G small A capital A S gallium arsenide in 2001 and 2002 processes for
growing gallium nitrate LEDs on silicon or successfully demonstrated. Fast forward to January 2012
and also demonstrated high powered lndium gallium nitrate LEDs growing on silicon substrates
commercially and gallium nitrate on silicon LEDs are in production at places and
semiconductors. White LEDs and illumination breakthrough. So even though white light can be created using
efficiency blue LEDs was quickly followed by the development of the first white LED and this device
a serium-doped force for coating produces yellow light through fluorescence. The combination
of that yellow with remaining blue light appears white to the eye. Using different phosphorus
produces green and red light through fluorescence. The resulting mixture of red, green and blue
is perceived as white light with improved color rendering compared to wavelengths from blue LED
YAG for several combinations. I've included a graph here that illustrates it's called
now I'm not sure you pronounce this. H-A-I-T is said it's low showing improvement in light output
per LED over time with a logarithmic scale on the vertical axis. So the first white LEDs were
expensive and inefficient however the light output of LEDs has increased exponentially. The latest
research in development has been propagated by Japanese manufacturers such as Panasonic and Nietzsche
and by Korean and Chinese manufacturers such as Samsung, Kingston and others. This trend and increased
output has been called, I'm going to mispronounce again, hit slow, H-A-I-T-Z, low, after Dr. Roland hits.
Light output and efficiency of blue and neutral LEDs rose on the cost of liable devices fail.
This led to relatively high power white light LEDs for illumination which are replacing incandescent
and fluorescent lighting. Experimental white LEDs have been demonstrated to produce
303 lumens per watt of electricity. Some can last up to 100,000 hours. However commercially available
LEDs have an efficiency of up to 223 lumens per watt. Below I've included some comparisons
for incandescent bulbs. So for example I've got figures here for a standard incandescent bulb
coming out at 12.6 lumens per watt and an example of a halogen bulb at 24 lumens per watt.
With LEDs continuing to get cheaper and even though for now they cost more than traditional
bulbs having this huge increase in electrical efficiency means overall cost is significantly
cheaper than that of incandescent bulbs. White indicator LEDs are known for the extremely long
life up to 100,000 hours as I previously mentioned. Lighting LEDs are operated much less
conservatively and consequently have shorter lives. LED technology is useful for lighting designers
because of its low power consumption, low heat generation and instantaneous on and off control.
And in the case of a single color LED continuity of color throughout the life of the diode
an relatively low cost of manufacture. LED lifetime depends strongly on the temperature of the
diode. Operating an LED lamp and conditions that increase the internal temperature
can greatly shorten the lamp's life. I now use LED lighting in my own home, particularly in the
areas where lighting is on extended periods such as in the living room. As you can see we have
come an extremely long way on a relatively short space of time with advancements continuing to
accelerate. It's hard to appreciate the massive impact electric lighting has had in the world.
It's even harder to imagine living at a time not that long ago where an expensive candle producing
a puny element of illumination was the only source of light with the added not-incrisisable
fire risk of having a naked flame, sharing a room with combustible materials. With all these
deterrents it's little wonder that people just went to bed when the sun went down.
Right well that's the end of my series on light bulbs and like. I hope you find it interesting.
If you want to contact me I can be contacted at MrX at hpr at googlemail.com
That's MRX, AT, hpr, the art symbol, googlemail.com. So until next time, thank you and goodbye.
You've been listening to Hecker Public Radio as Hecker Public Radio.org.
We are a community podcast network that release the shows every weekday Monday through Friday.
Today's show, like all our shows, was contributed by an HPR listener like yourself.
If you ever thought of recording a podcast and click on our country building to find out how easy it really is.
Hecker Public Radio was founded by the digital.com and the informomicon computer club
and is part of the binary revolution at bnref.com. If you have comments on today's show,
please email the host directly, leave a comment on the website or record a follow up episode yourself.
On this otherwise status, today's show is released on the creative comments,
attribution, share a like, to need our own license.