- The core technical principle of touch screen
At present, the mainstream touch screen technology is divided into two categories: resistive and capacitive, in addition to niche types such as surface acoustic wave screens and infrared screens.
1. Resistive touch screen: pressure triggered signal
Structure: Composed of two layers of conductive thin films (usually indium tin oxide, ITO) separated by tiny spacers.
Principle: When the finger presses the screen, the two layers of film come into contact, causing a change in current. The controller locates the touch point by calculating the voltage difference.
Features: Low cost, can be touched by any object (such as gloves, pens), but has poor transparency and does not support multi touch, gradually replaced by capacitive screens.
2. Capacitive touch screen: electric field induction
Structure: The surface is covered with a transparent electrode layer, forming a uniform electric field.
Principle: The human body carries a weak charge, and when touching the screen, it will "absorb" local charges, causing changes in the electric field. The chip determines the touch position by measuring the current change.
Features: Good transparency, fast response, supports multi touch, but requires finger or dedicated stylus operation. At present, mainstream projected capacitive screens (such as mobile phone screens) can also achieve pressure sensing and gesture recognition.
3.Other Technologies
Surface acoustic wave screen: locates touch points through the propagation time of sound waves on the screen surface, has strong scratch resistance, and is commonly used in public places.
Infrared screen: The edges of the screen are covered with infrared emitters and receivers, which block infrared radiation for positioning when touched, making it suitable for large-sized screens.
- Sensory upgrade of touch screen: haptic feedback technology
Modern touch screens not only rely on visual interaction, but also pursue "realistic touch". For example:
Vibration motor: Simulate the vibration feedback of button pressing.
Electro tactile sensation: By stimulating the skin with microcurrents, texture or resistance sensation is generated (such as Apple's Taptic Engine).
Ultrasonic tactile sensation: Using sound waves to create pressure on the surface of the screen, allowing fingers to feel virtual textures.
These technologies make it possible to "touch objects from afar" and may shine in fields such as virtual reality and remote healthcare in the future.
- The vast application scenarios of touch screens
- Consumer electronics: the core interactive interface of mobile phones, tablets, and laptops.
- Public services: self-service ATMs, ticket vending machines, government terminals to improve efficiency.
- Education and healthcare: Electronic whiteboards support multi person collaboration; The operating room touch screen assists in precise operation.
- Industrial control: The factory control panel commands the production line through a dust-proof and waterproof touch screen.
- Emerging fields: In car central control screens, smart home panels, and even flexible screens for foldable smartphones.
