The Nostalgic Nerds Podcast
The Nostalgic Nerds Podcast, where we take a deep dive into geek culture, tech evolution, and the impact of the past on today’s digital world.
The Nostalgic Nerds Podcast
S2E7 - The Age of Tiny Lights (LEDs)
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In S2E7, The Age of Tiny Lights, Renee and Marc trace the story of LEDs from a childhood electronics kit with a single red indicator to the decades-long effort to make blue light viable. What began as dim, specialised components required breakthroughs in crystal growth and materials science before becoming practical at scale.
Once blue was possible, white light followed, and with it, a steady transition away from a century of filaments and discharge lamps. Today, semiconductor light sits inside streetlights, buildings, vehicles, and displays, shaping energy use and the look of modern infrastructure.
There’s reminiscing about warm glowing lights, some justified moaning about modern headlights, and more than a little nerding out about materials science.
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Oh, I, my sister-in-law sent me a note about the tape. She listened. So she must've listened to the tape episode. And then I got a WhatsApp message about the tape and, and it was like, just totally random because she doesn't like text me, you know. Right. You know. Right. She texts my wife every day. You know, they have this little, what's that, what's that word game? Wordle. Wordle.
Renee:Oh, they're still playing Wordle,
Marc:Huh? Oh yeah. And I told them, don't use, don't play Wordle. Like the freaking New York Times is mining all your data and stuff.
Renee:Yeah, right?
Marc:Yeah, like whatever. So she texted me and says, hostage tape for over the mouth is used for those with sleep apnea. It encourages nasal breathing and limits snoring. So that's the name of it, hostage tape.
Renee:She's going to use hostage tape. I told you.
Marc:It's a thing. so so i'm not sure so i'm not sure if she listened to the episode and was like mouth tape i i'm gonna go check that out or if she already knew about it and then you know so that's crazy yeah yeah so yeah so for kim thank you for listening to the tape episode, and uh yeah hostage tape i think that's a weird name for it you know like to it's creepy.
Renee:It's That's super creepy. I don't think I'm into that at all, right? But okay.
Marc:Like, okay. I don't know. Maybe I'll try that, you know? I don't know. We'll see. Anyways. All right. So the other night, I'm talking to the youngest about the tape episode because we talked about the tape. I think it was coming back from Swim or something. And came up the inspiration for that one was one of the other kids, right? I was talking about, you know, my daughter. She needed tape. You know, we talked about tape. And so the youngest, she says to me, she wants me to do something that she suggested. And she says, you should do one on the light bulb. Yeah, of course. You know, the light bulb. I sort of laugh at that. I say, yeah, that's a good idea. So she gets excited. She wants to know that, you know, I'm crediting her in the episode as the inspiration.
Renee:Well done, youngest child.
Marc:There you go. There you go. So she gets excited, you know, and told her we'd do it. Okay. But then I'm thinking, what am I going to say about light bulbs? Because like it's sort of this you know for kids it's probably something that they hear a lot about thomas edison and filaments and glass and you know it's all like and people this is like well trodden area right so people people know this stuff so so i started thinking about it i realized this past week i'm actually kind of hugely nostalgic about glowy glowy lights i love i love glowy lights about it i don't know how else to say it really it's it's like one of these early memories that and i think about disneyland you know i love disneyland it's not like that you do that glow of main street right you know christmas lights and and i love drone shows anything that's got glowy or blinky lights i've got a little red led on my microphone here i'm just like i love it, you know the.
Renee:Data center blinking red and green
Marc:I know exactly okay so for me it's got a lot of like nostalgia here but the very first glowy lights that i remember came out of this like blue plastic case all right it's one of those 150 and one electronics kits and i don't know if you had one of these you know when you were a kid but i'm a girl.
Renee:I had a barbie
Marc:I wasn't gonna to say that but like.
Renee:Okay but go ahead
Marc:But we're you know we're of the generation that we're like gender gender stereotype toys yeah yes we did and yeah so it was one of those but it was like you get a radio shack or something right and and it was like this little board and it had a bunch of like electronic components on this board and there were little springs popping up on the whole board, and basically what you do is you take these little jumper wires and you lift the spring a little bit you know with your fingernail and you jam this this like exposed wire in and you make circuits you you kind of you know connect it all in you don't do any soldering or anything like that but you have this little book and you build little electronics things calculator an alarm you know whatever but the but the way that you knew that it was working was this little red led that was up on the top and it would glow, you know, and if you knew, if you got it right, that little tiny led would, would, uh, would do it. So, you know, you'd get it all together and if you got it wrong, it didn't light up. I didn't really understand what a diode was. I couldn't have told you about current flow or anything. I mean, I remember this when I was a little kid, but I understood if that little light turns on, the circuit was at least sort of correct. So looking back, I don't have like these strong memories of incandescent bulbs from childhood, but these glowy, small, tiny, blinky, you know, lights. I remember LEDs.
Renee:Okay. I do too. I had one of those Coleco handheld football games. You know the one where like the like the the interface you're looking at looks like a stadium but the actual piece of it that glows is only teeny tiny and then it has the football lines on it and then it's just it's a it's two defenders and like someone who obviously has a ball because you can't throw it you're always running right and you'd run back and forth back and forth back and forth and until everybody got all caught up and then you'd run right and you're just clicking buttons like go go go go go ah nine volt battery just keep going right like yes no graphics no screen really just little red dashes going up and it was a football game and then like the next year you got the good one it was when somebody else played defense so there's someone on that side there's someone on this side and you're both like trying to hold it steady while you're it was great you tilt didn't get the angle right because if you hit the if you if the light hit it wrong you I couldn't see anything, but I remember being completely obsessed with that thing. It was just blinking LEDs, and I gotta tell you, that was enough. Beep, beep, beep, beep, beep.
Marc:All right, folks. Hello. Welcome to another episode of the Nostalgic Nerds podcast, where we talk about history of tech and what it teaches us about the present and the future. Tonight, we're talking about LEDs, light-emitting diodes.
Renee:Before we get to the nostalgia, we should explain that a light-emitting diode, what it actually is. At its core, it's a semiconductor device. A diode means current flows in one direction. When electrons move across the material and recombine, they release energy in the form of photons. There's no real filament. Nothing's heating up until it glows. The light comes directly from electronic transitions inside the material.
Marc:The color depends on the energy.
Renee:Gap of that
Marc:Material.
Renee:Different materials emit different wavelengths, and that's the mechanism. That's why my Christmas tree can be a thousand different colors, all on the same light strand.
Marc:I love the Christmas, you know, you have the Christmas LEDs, man. That's trying to switch all of them to over that. Yeah, it's better. So, LEDs, it's not some overnight thing, man.
Renee:No, no, no. The phenomenon was observed in 1907 by H.J. Round. I'm going to look him up because I bet he looks like a nerd. Just
Marc:Like what was that richard drew or whatever his.
Renee:Name was whatever his name was he was super nerdy loved his glasses though he noticed certain materials emitting light under current it didn't go anywhere at the time but in 1920s oleg lossev sounds like someone who would stalk me honestly studied it more seriously he even suggested signaling application but vacuum tubes dominated that era. The first practical visible LED was demonstrated in 1962 by Nick Holinyak. Oh, that sounds like holodeck like that's pretty good right that's good it was red it was dim it was expensive red dominated because the semiconductor material engineers could reliably manufacture like gallium arsenide naturally emitted in the red and infrared range the band gap determined the color green and yellow took longer and blue was the real obstacle okay
Marc:So we're gonna talk about blue but like Like, I just, it just dawned on me for a second here, like, those infrared ones, like, you know, you know, remote controls on TVs used to be corded. Well, it's the, it was the little, you know, infrared LEDs that switched that away from being corded.
Renee:So you could lose it because it was no longer tethered to the thing it worked with.
Marc:Well, and then, you know, people would put cords on them and, like, attach them to the couch and stuff, you know. All right. So tell us about why was blue so difficult?
Renee:Well, blue light requires a larger band gap. That meant working with materials like gallium nitrate. Gallium nitride was extremely difficult to grow in high quality crystalline form. High defect densities reduced efficiency. So for years, blue emitters were dim and impractical. Researchers kept working on substrate materials, deposition techniques, and doping methods, but it took decades. And we don't mean doping like they were getting high and trying to figure it out.
Marc:No, no.
Renee:I mean, maybe they were, but I don't think that's it.
Marc:Well, no. All right. So, all right. I love the blue diode stuff. So this is kind of where it would get a little nerdy. I apologize.
Renee:Oh, it wasn't nerdy up until then, huh?
Marc:It was just a little nerdy. It was just a little nerdy. All right. And so on paper, gallium nitride should work, right? The band gap is right for blue. In practice, crystal growth was the bottleneck. We'll talk about this in a second here. So. So with the crystal growth, you have dislocations, defects, all kinds of structural issues that killed efficiency. Because, you know, there's got to be mass scale, right? You can't just, you know, you grow a crystal and make it work, but you got to grow thousands. And millions of these things. So, all right, here's where it gets technical, but it is important. So a semiconductor's band gap. So that's what we're talking about, like the difference between, you know, one side of, you know, the circuit and another. The band gap is the energy difference between the valence band, where electrons normally reside, and the conduction band, where they can move freely and carry current. When an electron crosses the gap and then recombines, the energy released can emerge as a photon. And the size of the band gap determines the wavelength, and therefore the color of the emitted light. Red light requires a smaller band gap than blue light, which is why early materials naturally produce red. To make efficient LEDs, the semiconductor crystal, the actual crystal, that's why they have to grow these, has to be grown with very low defect density because imperfections in the lattice of the crystal disrupt electron movement and provide non-radiative pathways where energy is lost as heat instead of light. You want more light instead of heat. High quality crystal growth is therefore not just a manufacturing detail, it directly determines brightness, efficiency, and reliability, And coming back to the practical now, okay, so that was a little, like, semiconductor, you know, nerdiness. In the 80s, in the late 80s and early 90s, Shuji Nakamura at Nichio, so it's a Japanese company, refined techniques for growing gallium nitride layers with much lower defect densities. Improved deposition for crystals, better doping strategies. So by the early 1990s, high brightness blue LEDs were commercially viable. Once you have blue, producing white light is straightforward. So up until this point, LEDs, like the closest you could get to white would actually be yellow. So to get white, you need a blue emitter combined with a phosphor coating that shifts part of the spectrum into longer wavelengths. And then your eye goes, oh, well, I believe that is white. And that's how most white LEDs work today. So this is a big deal. It's big a deal because this guy Nakamura, along with Isamu Akasaki and Hiroshi Amano, they received the Nobel Prize in Physics in 2014 for that work. So a large part of foundational LEDs, the IP and the manufacturing, actually remains with that company, Nichio.
Renee:Entirely in that company in Japan. Like they own LED.
Marc:Yeah. Yeah, like blue LEDs, which is super, like you can't have white LEDs without this blue technology. That's crazy.
Renee:As white LEDs improved, they started showing up in places where lighting runs constantly. Places like warehouses, hospitals, streetlights. Those are environments where lamps stay on for long periods and we're replacing them as a logistical exercise, not just a trip to a drawer in your house. An LED streetlight can operate for tens of thousands of hours before noticeable degradation. Incandescent bulbs don't operate in that range. High-pressure sodium lamps last longer than incandescent, but they still require periodic replacement. By the late 2000s, cities began retrofit programs. Utilities offered incentives. Commercial buildings upgraded in stages. Congress had so many meetings about, what, we have to change our light bulbs? I mean, it was ridiculous. Of course we have to change them. Quit being dumb. Early LED installations grew criticism for color temperature and glare. Those issues were adjusted over time. Yeah, you know what? You couldn't get a soft white bulb. You got the kind of white bulb where you could see the bones in your hand, right? Like, it's really, really white. Manufacturing scaled cost per lumen dropped Every time Sam looks at something and says, it's 1,500 lumens. And he's like, I have no idea what that means. Every time he says it to me, every time, I have no idea what it means. And I remind him that one lumen is one candlelight. 1,500 represents 1,500 candles. So, yes, right? So, cost per lumen dropped. Efficiency improved year after year. Now, in most new construction, LED is standard.
Marc:All right. So, look, before we go on, we should talk about the headlights. We should talk about the headlight issue. They're too freaking bright.
Renee:You know, honestly, you're right. You're right. I don't understand why I have to be blinded by large SUVs every time I'm going down the road. And you know what, though? I'll have to say this. Cybertruck, not so great. I'm never blinded by a Cybertruck. It has LEDs. I don't quite get it. Are they using Christmas lights in there? I don't know. I don't know. But a suburban, a suburban. And the thing that kills you is the stupid things are only three inches long. How did they get so bright? Like, that's crazy. That's you stare at the headlight while you're driving and you're like, I can't see anything anymore. Period. They're awful.
Marc:They're awful. They are awful. Here in the UK, I think the regulation in the UK and Europe was a little bit like a few years ahead of the US. So you didn't start seeing like some of the really obnoxious leds in the u.s we already had them in the uk for the last 10 years or something and but like i live out in the sticks there's no street lights you know there's like one lane roads you know and and they're so bright they're just i yeah i can't see the potholes in front of me when there's a car coming that's so darn I can't see anything.
Renee:I'm like, ah. And then if you're behind me, I have to just move the rearview mirror. I know. Because I'm going blind from the back. It's all awful. It's all awful. But at the same time, on the dark desert roads at night, I'm glad I have them. Right? I'm kind of glad. On a dark desert highway. I don't know what to do. Yeah.
Marc:With the cool wind in your hair.
Renee:Yes.
Marc:LEDs blasting. Yeah. Yeah. Yeah. So I think there's a lot of advantages. Right. But yeah, I got to say, like, I think I've got smarter.
Renee:Like they made them so that you can look around corners like they flip back and forth to look around the corner. Why can't they just tilt down when they realize they're coming up on like, you know, a roadster that is only three inches off the ground? Like, like, I don't understand that. I don't understand. Like, they have so many SUVs in the US. Like, like, for some reason, we default to gigantic car. Well, we're Americans. Like, bigger's better. And so, like, yes, of course, I drive an itty-bitty SUV, right, with LED lights. Of course. But I'm probably blinding someone in a Miata, but what do I care? At the end of the day, right, like, I think they should be smart enough to, like, tilt down, right? Just tilt down so that you don't blind oncoming traffic, especially. I mean, if we can have sensors that can drive the damn car for you, how come a kid just does that? It can turn my windshield wipers on when the windshield, like, feels rain. But it can't do that? No. No, no. Lexus. No. Like, figure it out.
Marc:They're Japanese. They've got the—they can figure this out. They've got the stuff. Like, figure it out. They've got the stuff. I mean, like—, You know, one of the problems with LEDs in housing residential use cases has always been directional versus diffusion, right? So LEDs are super, super directional. And it's because they lay them out on a board, you know, on a circuit board, and they stick the diode on there. And it's just a little, tiny little thing, right? But it's super directional. So they've developed strategies to diffuse them. But with so I'm thinking like with headlights, well, directional should be an advantage, right? Because then you could choose to turn on and turn off which LEDs and the directional array that you create. So that you're not blinding the stupid car in front of you, but you're lighting up the path around the car. Like you got radar in the cars for collision detection and all that. It should like LIDAR, right? It should detect the car in front of it and say, I'm not going to shine the lights right there on that car. I know it's a car. I don't need to blast it, shine the lights on the, you know, out like in other places where the car is not.
Renee:I know U.S. auto manufacturers are under a little bit of stress lately, but I'm just going to put it out there. Maybe you could help us out. Like, eventually, just kind of help us out. Maybe not this year. I get tariffs and all that, but, like, maybe in a couple years. A couple years? Help us out.
Marc:Yeah, help us out. I figure software plus hardware, like, we've seen this pattern many times, right?
Renee:Software plus hardware equals solution.
Marc:Yeah. Yeah. Okay. There's got to be a software solution to this problem here. All right. So. Coming back to this, lighting still represents a meaningful portion of global electricity consumption. As LEDs have replaced incandescents in fluorescence systems, you know, what was the big deal? Like people in Congress, you know, saying, oh, we'll bring back incandescents. Like, really?
Renee:Come on. Well, you know why? Because they all own stock in utility companies. And the more money you spend on your electricity, the more money they all make. Like, let's not be like that. That's exactly what it is. And go ahead i just yeah and for like the last so like like not not the last administration but the administration before it was like low flow toilets like can't flush them can't flush the toilet and now we're back to toilets again and paper straws so who the hell knows right like they have to complain about something and so they complained this year it's pennies wind turbines and we're back just toilets so
Marc:We'll see okay well we'll see i might it's hot To the high beam lights now. That's my thing. I feel like I'm Clint Eastwood, you know, telling the kids to get off my lawn. So, yeah. Anyways, all right.
Renee:We're that age now.
Marc:I know we are. LEDs replaced incandescent and fluorescent systems. Energy demand for lighting has declined in many regions, even as the number of light sources has increased. Incandescent bulbs convert much of their energy into heat. LEDs convert a far higher portion into visible light. Still, they have heat, though. It's a different problem. Anyways, that difference multiplied across billions of fixtures affects grid demand, hopefully in a positive way. There are environmental effects as well. Reduced electricity use lowers emissions, where grids rely on fossil fuels. Good. LED lifespans reduce replacement frequency and waste. Okay. All right. So I've got LEDs everywhere in the house. They still burn out like it's not like they're you know perfect and it ticks me off because this feels a lot like planned obsolescence because i know that a well-engineered light led light could last a very very long time and so i because it's me i i'm you know one of them burns out i pull it apart pull you know pop it off and see where the diodes are and then you could see the circuit board and then you go like wait what happened and they put crappy heat sinks and crappy resistors and stuff on the board and they just burn out it makes me mad anyways you.
Renee:Only paid like four bucks for it what do you want
Marc:Yeah but you know what like if i paid seven bucks for it then they would last three times as long you know like yeah.
Renee:But then what they would be lasting like 15 years and how do you make money on that like they guarantee them for five years Right. And I think five years is like enough that I, well, I have very high ceilings, like for me to change a bulb, it really is rough. But, you know, at least I want to do it once every five years. Right.
Marc:Yeah, true. All right. So, look, the phase out of mercury containing fluorescent lamps changes disposal dynamics like that's a good thing. So there's a lot of positive environmental impacts out of LEDs.
Renee:There are economic implications. Maintenance cycles are longer. Municipal budgets adjust. Commercial lighting designs shift toward integrated LED fixtures rather than replaceable bulbs. Manufacturing capacity is geographically concentrated. Gallium nitrate wafer production, phosphor chemistry, and LED packaging technologies are clustered in specific regions and firms. LEDs are no longer novelty components. They're embedded across infrastructure, residential, commercial, industrial, automotive, aviation, digital displays. The industry continues moving forward, though. Efficiency gains continue, though we're closer to theoretical limits in production.
Marc:One thing that's on the horizon is micro LED displays. Instead of backlights or organic emitters, microscopic inorganic LEDs act as individual pixels. Manufacturing yield. I know, is that cool? That's crazy. It is crazy. Manufacturing yield and mass transfer remain challenges, though. A gallium nitride is increasingly used in power electronics. High-frequency gallium nitride transistors appear in compact power supplies and chargers.
Renee:Lighting systems are becoming networked. LEDs integrate with sensor controls and building management system. Dimming and color tuning are standard capabilities. Yeah, you know what? You can go to Home Depot and get a light bulb and it's got every color in it. And some kind of crazy Bluetooth crap where you can just change it all the time. I don't know.
Marc:Do you have any of those?
Renee:I don't. But every Christmas I see them and I think, why not? Like, why not? Like, that'd be fun. Like, put them outside. That'd be fun. There's ongoing research into new semiconductor materials, improved substrates, phosphor stability, and advanced heat management. There's debates about light pollution and blue-rich lighting. There's research into circadian lighting and human biological response. My whole life runs by my circadian rhythm. Like, I'm sleepy when the sun goes down, wide awake when the sun comes up. Like, it is very, very well-tuned. And I think it would be cool if my bedroom lights could trick me. Like, could I sit in my bedroom with the lights on and my brain could think at nine o'clock at night, it's still light out. And then I set the lights to change their hue, right, to eventually make me sleepy and put me to bed at 11 instead of 630. Because that's where I'm like, like in the winter, I'm like, oh, man, it's 430. I'm so tired. Like, I'm not tired. This is stupid. But the sun went down. And so now I need to go to bed. It's just bad.
Marc:You should try living a little further north. It's even worse here.
Renee:Yeah, see, that's terrible. At any rate, the techniques developed to grow and process gallium nitrate for blue LEDs now underpin a range of other devices, from fast-switching power transistors to RF amplifiers and emerging micro-LED displays. Using LEDs for medical sterilization and water purification are two concrete outcomes of that research. Well, that's good. It's cheap. Right? Like, like, that's good.
Marc:Yeah, I think that, I mean, who doesn't want pure water, right? Who doesn't want, you know, sterilized, you know, hospitals?
Renee:Yeah, but if you used to do it with chemicals or UV, right? Like now you get to do it. So I have this thing where you can stick stuff in it and then you close the lid and it's UV and it sterilizes stuff. So, you know, any of my, like, you know, toenail clippers or micro needles I use on my face, like, all of that needs cleaned in a very extreme way. What do you got there?
Marc:This is my UV LEDs right here. I have that UV-curing resin, you know?
Renee:I use that to put my nails on.
Marc:Yeah, isn't it? It's so slick. They're like, oh, I'm going to blast you.
Renee:Yeah, no, I have one. It's like a big dome, and you stick your whole hand in it. Yeah, it's good. And it gets a little warm because there's so many of the LED UV stuff in it. So, yeah, I mean, like, yeah, I use it. Yeah, definitely we use it a lot anyway, right? Like, yeah, that's rad.
Marc:I think this is a lot of cool, you know, future developments there, particularly in the sort of medical and water stuff. I was doing some stuff with the foundation and, you know, their big thing is water, you know, water safety and water stability. And, you know, I think that they're considering different, you know, UV and LED solutions to purify water. I think it's cool.
Renee:So when I was when I worked at Forrester, I would have clients in pharma and they would talk about how in like how in third world countries, like they they said, like, the meds we have. Like would actually work in third world countries, right? Like they could cure dysentery, they can cure HIV, they can, or at least make it really treatable, right? They could do all that, but they, some places they don't because the water's no good. Like the first thing you have to do is get people clean water, right? Yeah. Yeah, and it's like, how do you do that in an economical way where, you know, you don't have to bring to bear water treatment facilities? Well, this is how you do it, right? Yeah, yeah, yeah. It's really, it is super important. it is like maybe not for me
Marc:Yet but.
Renee:Yeah you know what i mean no it's really really important so
Marc:I wonder i mean i have seen some of those those like portable purification kits and they include you know different lights and stuff you know and it feels a little bit feels a little bit like you know snake oil or something you know.
Renee:Could you imagine if it was just a light bulb? It was just a light bulb. Not drinking contaminated crap because you bought the cheapo one on Timu. Right? Yeah. Yeah, that's exactly what happened. Like, oh, I should have paid more than 75 cents for it.
Marc:Right. LEDs kill COVID. Oh, you can't believe that. Oh, but wait, they do. Oh, no. Yeah. Anyways. All right. So, look, from a tiny red dot in a plastic kit to streetlights and aircraft cabins, it's been a long arc. I didn't know what the band gap was when I was, you know, lifting those little springs on that kit with my fingernail. I just knew that the light came on when I got the thing right. So now most of the light around us isn't coming from something burning. It's coming from semiconductors doing exactly what they're engineered to do. And that's probably enough LEDs for one night. So if you enjoyed the episode, please take a moment to like, subscribe, share, do all the clickings and all of that. It genuinely helps other people to find us. If you have ideas for future episodes like this one or just want to say hello, you can reach us at NostalgicNerdsPodcast at gmail.com. There you go.
Renee:Thanks, everybody, for listening. I hope this was nerdy enough. I feel nerdy.
Marc:It was pretty nerdy.
Renee:I feel nerdy.
Marc:Gallium nitride, valence bands.
Renee:Right? It was super nerdy. Thanks for listening.
Marc:Thanks, everybody. Have a good day. You hold your shape, you don't lean.
