How The Touch Screen Works: The Science Behind This Popular Technology

Summary

This video from the Chrvoje Engineering channel explores the evolution and technology behind touch screens, starting from their invention in the 1960s by E.A. Johnson. It delves into the different types of touch screens, including resistive, capacitive, projected capacitive, surface acoustic wave, and infrared screens, explaining their unique functionalities and applications. The discussion highlights the significance of touch screens in modern devices, their operational principles, and the benefits and limitations of each type. By the end, viewers are encouraged to engage further through comments, likes, and subscriptions.

Takeaways

• 😀 Touch screen technology has become an integral part of modern life, often taken for granted in daily activities like scrolling on smartphones.
• 📅 The history of touch screens dates back to the 1960s when E.A. Johnson invented the first finger-driven touch screen.
• 🖥️ The first commercial touch screen was the HP-150, introduced in the 1980s, featuring infrared detectors for user interaction.
• 📊 Touch screens serve as both input and output devices, commonly found in laptops, tablets, and smartphones.
• 🔄 There are various types of touch screens, each with distinct working principles and applications.
• ✋ Resistive touch screens are widely used in ATMs and require pressure to register a touch; they are robust but have limited multi-touch capability.
• ⚡ Capacitive touch screens operate using electrical charges and are sensitive to touch without needing pressure, making them more responsive.
• 🧤 Projected capacitive touch screens (PCT) can detect touches even through surgical or thin cotton gloves, enhancing usability.
• 📡 Surface Acoustic Wave (SAW) touch screens use ultrasonic waves and provide high clarity but may struggle with water interference.
• 🌞 Infrared touch screens utilize a grid of infrared light beams to detect touch, offering excellent image quality but can be affected by sunlight.

Q & A

What is the significance of touch screen technology in modern devices?

Touch screen technology has become an integral part of daily life, enabling intuitive interaction with smartphones, tablets, and other devices, thus enhancing user experience.

Who invented the first finger-driven touch screen, and when?

E.A. Johnson invented the first finger-driven touch screen in 1965, which was outlined in his article published in Electronic Letters.

What was the HP-150, and why was it important?

The HP-150 was a computer launched in the 1980s that featured a 9-inch CRT display with infrared detectors, marking one of the first commercial applications of touch screen technology.

What are resistive touch screens, and where are they commonly used?

Resistive touch screens are commonly found in ATMs and supermarkets. They detect touch by pressing two conductive layers together, which requires firm pressure.

How do capacitive touch screens operate?

Capacitive touch screens operate by detecting the electrical charge of the human body, using a grid of electrostatic charges to sense touch without requiring pressure.

What are the two major types of capacitive touch screens?

The two major types of capacitive touch screens are surface capacitive touch screens, which use edge sensors, and projected capacitive touch screens, which allow for multi-touch functionality.

What is the working principle of surface acoustic wave (SAW) touch screens?

SAW touch screens use ultrasonic waves created by transducers on a glass panel. When a finger touches the screen, some of the waves are interrupted, allowing the system to detect the touch point.

What are the advantages of infrared touch screens compared to other types?

Infrared touch screens do not overlay the screen with additional layers, providing better image quality and clarity. They can also detect touches without pressure and work with various objects.

What limitations do resistive touch screens have?

Resistive touch screens have limitations such as reduced visibility due to multiple layers reflecting light, and they can only register single touches, unlike multi-touch capable screens.

How does sunlight affect infrared touch screen functionality?

Sunlight can interfere with the functionality of infrared touch screens, potentially affecting their ability to accurately detect touches.