Welcome everyone to techdaily.ai.

Great to be here.

Before we jump in, want to mention this deep dive is sponsored by StoneFly.

They're your trusted solution provider and advisor for enterprise storage, backup disaster recovery, hyper converged setups like VMware, Hyper V, Proxmox clusters.

Right.

AI servers too and things like the s a three sixty five turnkey security appliance plus public and private cloud solutions.

Exactly.

You can check out more info over at stoneply.com.

Definitely worth a look.

So today, we're taking that deep dive into something that's, well, literally at our fingertips almost constantly.

The smartphone touch screen display.

Yeah.

You know that feeling when you pick up your phone and it just works.

So seamless, almost like magic.

Mhmm.

We're gonna try and pull back the curtain on how that magic happens today.

It's really a fascinating mix of technologies that individually aren't exactly new.

That's right.

But they became truly revolutionary when someone figured out how to bring them all together effectively.

Right.

And what's really remarkable I think is how that simple act, just touching the screen, it hides so many layers of, well, pretty intricate engineering.

Yeah.

It's not just about one single breakthrough invention.

It's more like a symphony of existing tech all working together in a perfect harmony.

We're going to explore how three main layers combine to create that experience we all just, you know, take for granted now.

Okay.

So let's maybe start with the bigger picture.

Why did smartphones become so so essential?

I mean, most of us would honestly rather lose our car keys than our phone these days.

It's true.

Yeah.

And it's not just one single reason, is it?

No.

Definitely not.

You're talking about breakthroughs and app development, wireless Internet becoming, you know, everywhere.

Powerful carrier networks.

Yeah.

You just really smart marketing played a huge part.

Yeah.

But if we connect that back, I think the most important contributor was that seamless combination, that convergence of all these different functions and technologies into just one single package.

The ultimate convergence device.

Exactly.

You just put everything you needed in one place.

And the touch screen.

Well, you could argue it's the star of that show.

Right?

It's the interface that made everything else so easy to use together.

Absolutely.

It's the gateway.

But what's interesting, like you said, is that these weren't brand new technologies in isolation.

I mean, we'd had tactile interfaces on other devices.

Sure.

ATMs, kiosks.

Right.

And color displays were pretty standard by then and even toughened glass.

That concept had been discovered way back in the eighteen hundreds.

Which, really raises an important question then.

If the individual bits weren't new, what was the big innovation?

Yeah.

And it really was that flawless integration, layering them together, making them work seamlessly.

That's what made the smartphone feel revolutionary.

It was the execution.

So it wasn't inventing a new ingredient maybe, but perfecting the recipe using existing ones.

That's a great way to put it.

Yeah.

Like the difference between having flour, eggs, and sugar, and having a perfectly baked cake.

Okay.

And you mentioned three distinct layers in that recipe.

Let's start peeling them back.

Layer one, the one right on top that we're always touching.

The protective glass.

Mhmm.

We've all seen shattered screens, unfortunately.

But think about how many times you've probably dropped your phone and it hasn't shattered.

That can't just be luck.

No.

Definitely not luck.

And it's easy to forget, but before the first iPhone arrived in 02/2007, most mobile phone screens were actually plastic.

Oh, yeah.

I remember those.

And while plastic doesn't shatter like glass, it scratches so easily.

Just imagine your screen covered in dozens scratches after like a week in your pocket next to your keys.

Yeah.

Pretty unusable, pretty fast.

Right.

So what makes this modern smartphone glass so much stronger than say just a regular piece of window glass?

It's a special type, an aluminosilicate glass, and it goes through this really clever chemical strengthening process.

They basically soak it in a bath of molten potassium nitrate, a hot salt bath, essentially.

Okay.

A salt bath.

Sounds simple, but what's actually happening there on, like, an atomic level?

Well, that's where it gets interesting.

During that soak, the smaller sodium atoms already inside the glass structure tend to migrate out.

And much larger potassium atoms from the bath move in and take their place.

Larger atoms forcing their way in.

Exactly.

And because these potassium atoms are significantly bigger they get squeezed into the spots the sodium atoms left.

This creates a really substantial compressive force right there on the surface of the glass.

Okay.

Compressive force.

Let me try an analogy.

Is it like imagine you have the backseat of a car and you fit three average sized people in.

They fit.

Okay.

But they can still kinda move around a bit.

Right.

Now replace those three people with three huge football linebackers.

They might just barely squeeze in, but once they're in, they are absolutely packed solid.

It would take way more force to push them around or get them out right.

That's actually a perfect analogy.

That's the fundamental idea.

The surface atoms are under compression, packed incredibly tightly.

So it requires significantly more force to initiate a crack or a scratch.

That compression provides incredible durability against well everyday hazards like scratches and even many drops.

So that tight packing those atomic linebackers are protecting the screen.

Got it.

Okay.

So that's the super strong glass on top.

What's directly underneath that?

Layer two?

Right below the glass is the layer that actually senses your touch.

That's the projected capacitive touch screen.

Projected capacitive.

Yeah.

Okay.

How does that actually work?

How does it know my finger is there?

Well, this layer is made up of two transparent diamond grid patterns.

Think of like invisible intersecting lines.

Oh, okay.

These grids are printed usually on a clear polyester film and there's an optically clear insulator sandwiched right between them.

And the grid lines themselves, what are they made of if they're invisible?

They're made from a transparent conductor.

The most common one is called Indium Tin Oxide or ITO for short.

So you've got this invisible grid.

Okay.

Invisible wires.

So let's oom in.

If you build up electrons, like a negative charge on one part of that grid Mhmm.

Say one line of diamonds.

Let's call them the blue diamonds, hypothetically.

Okay.

The blue diamonds get a negative charge.

Now because there's that insulator layer, the electrons can't just jump across.

Right.

They're stuck.

But their electric field can reach across.

And that negative field causes positive charges to accumulate on the corresponding diamonds on the other grid layer.

The yellow diamonds.

Let's say yellow.

Yeah.

Right.

So you have negative on positive drawn to yellow, separated by an insulator.

That's set up.

That's essentially a tiny capacitor.

The screen is full of these tiny capacitors.

Ah, okay.

Capacitors.

I remember those from physics.

So how does my finger fit in?

Well, your fingertip is conductive that holds a small electrical charge itself.

So when your finger gets close to one of these tiny capacitors on the screen, it disrupts that delicate electric field between the blue and yellow diamonds.

It changes the amount of positive charge that could be stored on the yellow diamond.

So my finger messes with the charge.

Exactly.

The phone's processor is constantly monitoring the charge on all these capacitors.

When it detects that change caused by your finger, it registers it as a touch at that specific point.

Okay, that makes sense for one touch but how does it know exactly where I touched and how does it handle like pinching to oom with two fingers multi touch?

Ah, good question.

It finds the location it sends a signal activating the charge along one set of grid lines say the blue rows one after another very quickly.

Okay.

And while it's activating each blue row it's simultaneously measuring the charge level on all the perpendicular yellow columns.

Ah, like coordinates on a map.

Precisely.

Since each blue row is connected and each yellow column is connected, this creates a grid reference.

It's too complex and slow to measure every single intersection point individually.

Right.

So instead it sends the charge down each row in rapid succession and reads all the columns simultaneously.

This allows the processor to pinpoint the coordinates of multiple touches at the same time.

And it gets all done with transparent ITO and insulators so you look right through it to the display underneath.

Wow.

That's that's really clever engineering hidden in plain sight.

Okay.

So we have strong glass then the invisible touch grid.

What's the third layer?

The part that actually shows us the picture.

That's the display itself.

Now older phones and some budget models might still use LCD, liquid crystal display technology, but most modern smartphones, especially higher end ones use OLED.

OLED.

Organic Light Emitting Diode.

Exactly.

And this is what generates those really stunning vibrant images you see.

And the quality is amazing now.

It really is.

And what's fascinating here again is the sheer density.

Current high end phones can have over say 3,300,000 pixels crammed into that screen.

3,300,000 tiny picture elements.

And remember each pixel is typically made of three sub pixels, a red, green and a blue one.

So do the math.

That means you literally have close to 10,000,000 microscopic individually controlled dimmable lights, red, green and blue right there in the palm of your hand.

10,000,000, just pause and think about that for a second.

10,000,000 tiny lights.

The engineering just to design that let alone manufacture it reliably.

It's kind of mind boggling.

It absolutely is.

Each OLED display is essentially this massive grid of individual pixels.

Each pixel has its red, green, and blue sub pixel components.

Right.

And the brightness, the intensity of each of those tiny sub pixel lights is controlled by an equally tiny electronic component called a thin film transistor or TFT.

A TFT?

Yeah.

Think of it like a microscopic dimmer switch for each individual red, green, and blue light source.

Millions of them.

Okay.

Millions of dimmer switches.

So how do these little OLEDs actually produce light?

Are they like tiny incandescent bulbs?

Not quite like bulbs, but they do emit light directly.

Fundamentally, photons like particles are produced when electrons are driven from a negative terminal to a positive terminal.

Okay.

And as they travel, they pass through a special middle layer called the emissive layer.

This layer is made of specific organic compounds.

Organic, hence the O in OLED.

Exactly.

When the electrons pass through this emissive layer, they release energy in the form of photons light.

And the specific organic compounds used in that emissive layer determine the color of the light produced red, green or blue.

And the intensity or brightness depends on how many electrons are pushed through, which is controlled by that thin film transistor, the dimmer switch.

So different materials for different colors and the transistor controls the brightness.

That's the basic principle, yes.

Now, this is obviously a simplified explanation.

The actual research and science behind developing efficient and long lasting OLEDs, especially the blue ones, is incredibly complex.

Yeah, that

In fact, it's so significant that the 2014 Nobel Prize in Physics was awarded to three researchers specifically for their work that led to efficient blue light emitting diodes, which was a crucial piece of the puzzle for full color displays like this.

Wow.

Nobel Prize winning technology in our pockets.

That really puts it in perspective.

Oh, isn't it?

So let's recap for everyone listening.

What does this all mean when you look at your smartphone screen?

You're essentially looking at this incredibly engineered technological sandwich.

Sandwich is a good word for it.

Right.

On the very bottom you've got that OLED display with maybe 10,000,000 tiny individually controlled red, green, and blue lights creating those vibrant sharp images.

Mhmm.

Then layered right on top of that display is the transparent projected capacitive touch screen grid that invisible network that precisely senses where one or even several of your fingers are touching simultaneously.

Yep.

The invisible sensor.

And finally on the very top protecting everything is that chemically strengthened glass, fighting off scratches and giving your phone a fighting chance when you inevitably drop it.

That's the stack.

Glass, touch sensor, display.

All laminated together perfectly.

Amazing.

So, yeah, maybe the next time you pick up your phone, just take a second.

Consider the, conceptual simplicity of just touching a screen, but also the incredible structural complexity hidden just beneath the surface.

It's a testament to some amazing engineering.

It really is.

You're now a touch screen expert.

Well, maybe not expert, but hopefully have a better appreciation.

Definitely.

And hey, before you go, we wanna give one last shout out to our sponsor, Stonefly.

They've got a pretty compelling offer right now.

A 100 terabyte immutable and air gapped SSO NS, that's network attached storage, for just $8,995

Wow.

A 100 terabytes immutable air gapped.

That's some serious data security capacity Yeah.

For that price

Definitely a powerful and secure solution if you're dealing with critical data.

Again, check them out at stonefly.com.

Thanks everyone for joining us for this deep dive.

Thanks for listening.