Expert guide to touchscreens used in modern gadgets

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Touchscreen technologies are evolving at an increasing pace as devices equipped with them surround consumers across their daily lives – from smartphones and tablets to vending machines, kiosks, and ATMs. All of these devices used touch panels that enable the interaction between users and machines without the need to use anything else, like a mouse or keyboard. 

The touchscreen solutions used today come with specific advantages and drawbacks. If you’re looking for more information about this, keep on reading. In this article, we go over the most important types of touchscreens used in modern gadgets today.

Expert guide to touchscreens used in modern gadgets

1. Resistive touchscreen

A resistive touchscreen is made of a glass panel and a film screen. These two are covered with a thin metallic layer separated by a small gap. Here’s how a resistive touchscreen works: when you touch the screen, the two metallic layers meet to create an electrical flow. The change in voltage identifies the point of contact. The voltages are then converted into X and Y coordinates and sent to the controller. 

Today, the most popular technologies are the 4-wire resistive touchscreen for its high accuracy and cost-effectiveness – and the 5-wire touch screen that comes with a longer lifetime and can be activated by a finger, stylus, or a gloved hand. 

Pros:

  • It can be activated with practically any object, whether it’s a gloved hand, finger, pen, stylus, or something else. 
  • It’s the lowest cost alternative among other touchscreen technologies available today. 
  • It’s resistant to surface contaminants and liquids such as grease, oil, moisture, or dust. 
  • It offers a tactile feel to users.
  • It has lower power consumption. 

Cons:

  • It offers lower image clarity compared to other touchscreen technologies. 
  • The outer polyester film can be damaged by scratching or poking it with sharp objects. 
  • The resistive touchscreen doesn’t offer multi-touch functionality. This is why today PCAP touch screens are replacing resistive touchscreens in many applications that used to be the domain of resistive only. This is especially true for environments that require using gloves or where water may fall on the screen.

2. Surface capacitive touch screen

Capacitive touch screens are part of most consumer products such as tablets, laptops, and smartphones. Thanks to technological advancement, capacitive touchscreens are replacing resistive touchscreens due to greater capabilities in dealing with moisture or the use of hand gloves. 

One of the most popular types of capacitive touch screens is the surface capacitive touch screen. It consists of a transparent electrode layer located on a glass panel and placed in the protective cover. 

When you touch the monitor screen with your finger, the screen will react to the static electrical capacity of the human body. Some of the electrical charges will be transferred from the screen to the user, and sensors located at four corners of the screen will identify the decrease in capacitance. 

That’s how they allow the controller to identify the touchpoint. That’s also why capacitive touch screens can only be activated when touched by a human finger (or a special stylus with an electrical charge). 

Pros

  • It offers higher image clarity than a resistive touchscreen. 
  • It comes with excellent durability and outstanding resistance to liquid and surface contaminants like grease, oil, dust, and water. 
  • It has high scratch resistance. 

Cons

  • It requires a bare human finger or a capacitated stylus or glove for activation. 
  • It’s sensitive to EMI/RFI.

3. Protective capacitive touchscreen (PCAP)

This type of touchscreen offers two main advantages over the surface capacitive touch screen. First of all, it can be activated by a bare finger but also thin cotton gloves or surgical gloves. Second, it allows multi-touch activation by placing two or more fingers together on the screen to unlock extra functionalities. 

How does the PCAP touchscreen work? The touch screen comes with a sheet of glass into which manufacturers embed transparent electrode films and an IC chip. This is how a 3D electrostatic field is created. When you touch the screen, the ratios of electrical currents change instantly, and the device detects the touchpoint immediately. 

Pros

  • Excellent image clarity. 
  • More resistance to scratching than the resistive touchscreen. 
  • Excellent resistance to liquids and surface contaminants like moisture, dust, grease, oil. 
  • Multi-touch functionality by allowing two or more touchpoints at the same time. 

Cons

  • Sensitive to EMI/RFI.
  • Can be activated using a bare finger, special stylus, or thin gloves.

4. SAW (Surface Acoustic Wave) touch screen

This type of touchscreen uses piezoelectric transducers and receivers located along the side of a glass plate. They create an invisible grid of ultrasonic waves on top of the surface. When you touch the top of the screen, some of the waves will be absorbed, and that’s how the receiving transducer can identify the touchpoint and send the data to the device. SAW monitors can be activated with a bare hand, gloved hand, or a soft tip stylus. 

Pros 

  • Outstanding clarity, durability, and resolution. 
  • Excellent scratch resistance – much better than surface or projected capacitive touch screens. 
  • Higher touch life.

Cons 

  • This touchscreen can’t be activated with hard items like pens or fingernails. 
  • Water droplets on the screen may cause false triggering. 
  • If the screen is covered in solid contaminants, they might create a non-touch area until they are removed. 

5. Infrared (IR) touchscreen

An infrared touch screen doesn’t require manufacturers to overlay the display with any extra screens or sandwiches. Instead, it takes advantage of infrared emitters and receivers to create a grid of light beams across the screen that are invisible to humans. 

This is also how the touchscreen offers an amazing image quality. When an object interrupts the infrared light beam, the sensor can easily identify the touchpoint and send the X and Y coordinates to the controller. Often used in outdoor locations, infrared touch screens offer excellent durability and can detect practically any type of input. 

Pros

  • The highest limit clarity and light transmission compared to all the touchscreen technologies on the market. 
  • Practically unlimited touch life. 
  • Resistance to surface scratches. 
  • Multi-touch functionality. 
  • It offers a Palm Rejection Capability. 

Cons

  • It’s relatively easy to accidentally activate the screen, given that infrared beams are on top of the glass surface. 
  • The buildup of oil, dust, and grease on top of the screen or the frame might prevent the light beams from proper operation. 
  • Pooling of water and a buildup of snow might cause false triggering. 
  • The type of screen might be too sensitive to direct high ambient light interference. 
  • It’s the most expensive technology out of all the ones we’ve covered.

How to choose the best touch screen for a modern gadget? 

When it comes to picking the right touchscreen technology for a new device, manufacturers first take a look at its unique requirements. 

By picking a resistive touchscreen, you can lower the cost, get a high resolution, and reduce the possibility of accidental touches, which might be important in some environments. On the other hand, PCAP touch screens are more durable and offer an excellent quality of images with superior sharpness and contrast. They also support multi-touch sensing that consumers enjoy. 

All in all, the use of touchscreen technology depends on the unique requirements of each and every mobile device, including the preferences of its users. We look forward to seeing what the future will bring for touchscreen technologies.

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