Have you ever wondered how your phone screen can detect your touch? It’s like magic, right? Well, it’s not magic, but rather a combination of science and technology. Let’s break it down step by step.
Step 1: Get Some Glass
First, we need to create the glass screen. We start with high-purity silica sand, melt it, and pour it into a mold. Voilà! We have glass. But this glass is fragile, so we need to make it stronger. That’s where Gorilla Glass comes in – a chemical treatment that makes the glass more durable.
Step 2: The Touch
There are two types of touch screens: the one used in your phone and the annoying kiosk at McDonald’s. Let’s start with the latter. The McDonald’s kiosk has two layers – plastic on top and glass behind – both covered in a conductive material. When you touch the screen, it creates electricity, and the processor can detect where you touched. But how? The conductive material is applied in a precise grid pattern, so when you touch the screen, it sends electricity to the processor, which matches it to what’s on the screen.
The other type of touch screen, used in your phone, has four layers. The top layer is the tough glass we created in step one. Below that are two clear diamond-shaped grids with an insulator in between. These grids are made of a material that holds electricity well, and when you touch the screen, it disrupts the electric field, causing a change in the positive charge on the top layer. The processor then detects this change and matches it to what’s on the screen.
Capacitors
The two grids create a capacitor, which builds an electric field. When you put something that conducts electricity, like your finger, near the capacitor, it messes with the electric field, changing the positive charge on the top layer. This is how your phone detects touch.
Why Touch Screens Work with Fingers but Not Gloves
Your finger and a hot dog conduct electricity, which is why touch screens work with them. But gloves are insulators, so they don’t change the electric field, and your phone can’t detect touch. Water conducts electricity, but when your hands are wet, it activates multiple points at once, confusing your phone.
Display
Now that we have our glass and touch screen technology, let’s talk about the display. You might think you know how pixels work, but let’s zoom in really close. Each pixel is made up of three baby pixels – red, green, and blue – with a dimmer on top. By adjusting the dimmer, we can create any color. With millions of pixels, we can create any image.
That’s it for now! I’ll stop here and wait for your confirmation to continue with the second half of the blog post.
The combination of red, green, and blue baby pixels creates a wide range of colors, and with millions of pixels, we can display high-quality images and text. But how do we control these pixels?
Backlight
Behind the pixel layer, there’s a backlight that shines through the pixels to illuminate the images. This backlight is usually an LED (Light Emitting Diode) that produces white light. The light passes through the pixels, which filter out certain colors to create the final image.
LCD (Liquid Crystal Display)
The pixel layer is made up of Liquid Crystals, which are like tiny shutters that open and close to control the amount of light passing through. When an electric current is applied, the Liquid Crystals align to block or allow light to pass through, creating images on the screen.
OLED (Organic Light-Emitting Diode)
Some displays use OLED technology, which is different from LCD. OLED pixels produce their own light when an electric current is applied, so they don’t need a backlight. This results in deeper blacks, as the pixels can turn off completely, and more vibrant colors.
Touch Screen and Display Together
Now that we have our touch screen and display technologies, let’s put them together. The touch screen detects your touch and sends the coordinates to the processor, which matches it to what’s on the screen. The display then shows the image or text, and when you touch the screen, it responds accordingly.
That’s the basic technology behind touch screens and displays! It’s a remarkable combination of materials science, electrical engineering, and computer science that enables us to interact with our devices in a intuitive and visual way.
The Evolution of Touch Screens
Touch screens have come a long way since their inception. Let’s take a brief look at their history:
1965 – The First Touch Screen
Eric Johnson, an engineer at the Royal Radar Establishment in England, developed the first touch screen. It used a stylus and was used in air traffic control systems.
1970s – Resistive Touch Screens
The first resistive touch screens were developed, using a flexible plastic sheet and a metal wire grid. These were used in early smartphones and PDAs.
1980s – Capacitive Touch Screens
Capacitive touch screens emerged, using electrodes and a glass or plastic surface. These were more sensitive and accurate than resistive touch screens.
1990s – Touch Screens in Consumer Devices
Touch screens started appearing in consumer devices like smartphones, tablets, and touch-tone phones.
2007 – The iPhone Revolution
Apple’s iPhone popularized multi-touch gestures, like pinching and swiping, and introduced capacitive touch screens to the mainstream.
Present Day – Advanced Touch Screens
Modern touch screens use advanced materials, like Gorilla Glass, and technologies like OLED and 3D Touch. They’re also becoming more responsive, accurate, and energy-efficient.
The Future of Touch Screens
What’s next for touch screens? Some trends and innovations include:
1. Flexible and Foldable Displays
Flexible OLED displays are already here, and foldable devices are emerging.
2. 3D Touch and Haptic Feedback
3D Touch and haptic feedback technologies are enhancing the user experience.
3. Artificial Intelligence and Machine Learning
AI and ML are improving touch screen responsiveness and accuracy.
4. Augmented Reality and Virtual Reality
Touch screens will play a crucial role in AR and VR experiences.
5. Biometric Authentication
Touch screens will integrate biometric authentication methods like fingerprint and facial recognition.
The evolution of touch screens continues, with innovations and advancements pushing the boundaries of user interaction and experience.
(To be continued…)
Let me know when you’re ready for the next part!
The Science Behind Touch Screens
Let’s dive deeper into the science behind touch screens:
1. Electromagnetic Induction
When you touch a capacitive touch screen, your body acts as a conductor, allowing electricity to flow through your skin. This creates an electromagnetic field that induces a voltage change in the electrodes beneath the screen.
2. Electric Field Distortion
When your finger approaches the screen, it distorts the electric field around the electrodes. This distortion is detected by the controller, which calculates the exact location of your touch.
3. Capacitance and Resistance
Capacitive touch screens measure the change in capacitance between the electrodes and your body. Resistive touch screens, on the other hand, measure the change in resistance when you press on the screen.
4. Surface Acoustic Waves
Some touch screens use surface acoustic waves (SAW) technology. When you touch the screen, you disrupt the SAW pattern, which is detected by sensors.
5. Infrared and Optical Technology
Some touch screens use infrared or optical technology to detect touch. These screens emit infrared or optical beams, which are interrupted when you touch the screen.
The Brain-Computer Interface (BCI)
Touch screens are also being used to develop Brain-Computer Interfaces (BCIs). BCIs enable people to control devices with their thoughts, using electroencephalography (EEG) or other technologies.
Neurological and Biomedical Applications
Touch screens are being used in neurological and biomedical research to study brain function, motor control, and sensory perception.
Assistive Technology
Touch screens are also being used to develop assistive technology for people with disabilities, such as screen readers, magnification software, and alternative input methods.
The science behind touch screens is fascinating and continues to evolve, enabling new technologies and applications that transform the way we interact with devices and each other.
