Skip to main content

How Do Touchscreens Work?

How do Touchscreens work? What enabled smartphones to dominate as a technology- to be so prolific and critical to our lives that I I would rather lose my car keys or wallet than my smartphone. The answer to this question isn’t a simple one liner, but rather it's a combination of answers, app development, wireless internet, carrier networks, Steve Jobs’ brilliant marketing, tho I would argue the most important contributor was the seamless combination of different functions and technologies into a single package. In this episode we're going to explore the most distinctive feature of the smartphone’s merging of technologies- the touchscreen display.

There are three technologies within the touchscreen display These technologies are combined all on top of every other. When you felt and used a smartphone for the first time, you just knew that you were holding something revolutionary – something different from all previous phones. These… were not new technologies. Many devices used a tactile interface, and color displays had already been a typical for many phones. Even toughened glass had been discovered in the 1800 s. 

But the innovative element was combining them seamlessly. One layer on top of another like magic. Ok, so let’s get into the layers of a touchscreen display. On the top, we have the protective glass. A lot of us have had a screen shatter but think about how many times you’ve dropped it and it hasn’t. That’s because a smartphone’s glass is over 5x stronger than normal glass. And, before the first iPhone showed up in 2007 the standard for cellphone screens was plastic and although plastic doesn’t shatter, it is very easily scratched. If the screen were covered in plastic, it wouldn’t last a week sitting in your pocket next to your keys before having dozens of scratches all over it. 

So, what makes toughened glass so much stronger? A smartphone’s glass is an terminological glass that is toughened by soaking it in a bath of molten potassium nitrate. This causes the sodium atoms within the glass migrate out, and far larger potassium atoms take their place. Because the potassium atoms are much larger, they generate a substantial compressive force on the surface of the glass. 

Here’s a quick analogy: imagine filling the backseat of a car with 3 average sized people. They fit snugly but if you push them, they're still able to move. Now replace those 3 people with 3 football linebackers.Those linebackers are just flat out stuck- unable to move. It would take much more force to move those linebackers from their seats. This is the elemental concept behind what makes toughened glass special, the atoms are compressed so it might take more force for the glass to interrupt . Below the toughened glass may be a projected capacities touchscreen that senses the presence and site of conductive materials,such as your finger tip. 

This touchscreen is composed of two transparent diamond grid pattern sprinted on polyester with an optically clear insulator in the middle. Let’s take a closer look on how it works. say we build up a bunch of electrons on this blue diamond, however because there is an insulator in the way, the electrons cannot move. The electrons generate a negative electric field which causes a bunch of positive charges to build up on the yellow diamond This is called a capacitor. Now, when we move a conductive material such as the tip of your finger close to this capacitor it disrupts the electric field which changes the amount of positive charges that build up on the yellow diamond. The change in positive charges caused by this disruption on the yellow diamond is measured, and the processor registers this as a touch. 

The location of the touch is detected by scanning the charges or voltage along the blue diamond rows, while actively measuring each yellow diamond column. Note that each row of blue diamonds is connected together, also each column of yellow diamonds is connected. This setup makes a grid of blue columns and yellow rows. Just to clarify again, all of these components are made with transparent materials. Measuring each point requires an excessive amount of circuitry, so we only measure each column. The charge or voltage gets sent to each row in quick succession, so the processor can register multiple touches at once Below that is a display which uses LCD or OLED technology. 

While the LCD and the OLED display both produce high quality images, in this episode we are going to focus on the OLED technology as it is the standard in most new Smartphones. OLED stands for Organic light emitting diode. This high-resolution OLED display is what generates the high-quality images that we see whenever we glance at our smartphone. This is a crazy intricate grid! Current 2018 high-end phones can have over 3.3 million pixels. That means there are 10 million microscopic individually controlled dilemma red green and blue lights in the palm of your hand. Take a moment to think about the engineering level recurred to control let alone design and manufacture that many microscopic lights! OLED displays are composed of a massive grid of individual pixels and each pixel is composed of a red green, and blue sub pixel. 

Each sub pixel's candlepower is controlled by a little thin film transistor that acts as a dimmer switch. There are many layered structures in each sub pixel, however explaining the function of each layer will have to be saved for a future episode. Photons are produced in the sub pixel by electrons that are driven from the negative to the positive terminal. When they pass through this middle layer here, called the missive layer,photons are emitted through a release of energy. The compounds used to make up the missive layer determines the color of the light emitted, and the intensity of this light is dependent on how many electrons pass through. 

In fact the 2014 Nobel prize in Physics was awarded to 3 researchers for their discovery of efficient blue light emitting diodes! So, let’s summarize: on the bottom is an OLED display composed of a 10 million itty bitty little colored lights. On top of that is a transparent projected capacitive touchscreen that can sense one or multiple finger touches at a time. And on top of that is strengthened glass that protects your screen from scratches and most falls. Now you too are a touchscreen expert! If you have any questions, post them to the comments below. Subscribe, Like, and tell your friends or family about something you learned. This episode details the structure of a touchscreen display. 

Branches from this episode are: Multi touch design, electric fields, Capacitors OLEDs and their control, LCDs, Why are materials transparent? And interface aesthetics. Thanks again for watching and until next time, consider the conceptual simplicity yet structural complexity in the world around us.


Popular posts from this blog

Marvel Shang Chi Teaser 2020 Breakdown - Avengers Iron Man Phase 4 Easter Eggs

You see there's somebody who wants to meet you you don't know him no but you took his name and now he wants it back no sorry i still don't get it it is western Sydney home to the newest edition of the marvel movie franchise the seven news chopper captured these scenes today as work resume building the set for the upcoming production shag chi and the legend of the ten rings it's understood that all cast and crew have now arrived from overseas and after completing their required quarantine shooting will begin in the coming days 18 weeks later than originally planned welcome back everyone it's charlie so we have a brand new marvel shag chi clip to break down there's a whole bunch of stuff going on with the movie because marvel's starting to film all their movies again.

Thankfully things are getting going so we'll break it all down there's a bunch of Easter eggs if you're new to the channel be sure to subscribe to get all the videos we're doing…

The Science and Technology of Tomorrow

Today the majority of our energy comes from fossil fuels we find beneath the earth in the form of cool natural gas and oil We've seen a rise in renewable energy, but fossil fuels are still the main source and without them the economy would collapse But these are going to become harder and harder to find and extract in the efficient way Which way I'll turn the forms of energy are going to take over Solar is one alternative That's becoming more and more popular although it is more expensive to get power from solar energy Currently the cost of fossil fuels is going to rise and the cost of solar is falling once equilibrium is met market forces will do the rest and note that solar cells are actually not that efficient so to engineering options are to make them more efficient or Reduce the cost to make and install these in bulk these are two directions that research has gone Wind is another popular form of energy.

 But it will not be what supplies the bulk of energy for the wor…

How 5G works: the pros and cons

5G internet. We've been talking about it for a short time, and now it's finally beginning to arrive. It is a revolutionary entirely internet that promises to change everything from your Phone, to home internet, to more futuristic fields like self-driving cars and even remote surgery, but 5G's also been within the headlines lately for tons of wrong reasons with bizarre conspiracy theories and rumours. So, to assist bright things up, we're going to inform you, what exactly 5G is, how we came, what the technology behind it is, and any real concerns which may exist around the new technology. (chill music) So, what's 5G? Well, 5G or fifth generation, is that the next step in mobile internet technology.

It's what all of the next waves of phones and tablets are going to use for speed that is even faster than the LTE network that we have already got. Now, our news editor and reviewer, Chris Welch, has been testing all these networks for a while already, so he can tell…