In our daily lives, we’re surrounded by touch screens constantly. We see them in smartphones, tablets, ATMs, ticket vending machines, kiosks, and even manufacturing plants. All of these examples use touch panels to enable easier interaction between users and computers, without having to use a keyboard or mouse.
Did you know that today manufacturers offer several types of touch screens? If you’re looking to build an application that requires a touch screen or you’re simply curious about the novelties on this exciting market, this article is for you.
Read on to learn the key types of touch screens in production today, together with their advantages and drawbacks. We hope reading this article helps you make a more informed decision about your application.
1. Resistive touch screen
A resistive touch screen monitor is made of a glass panel and a film screen. They are both covered with a thin metallic layer, which is separated by a small gap. When the user touches the screen, these two metallic layers meet, creating an electrical flow. The change in voltage detects the point of contact – the voltages are converted into X and Y coordinates, later sent to the controller.
Resistive touch screens come in 4, 5,6, 7, and 8-wired models, differentiating between various coordinates of the touch. The most common technology today is the 5-wire resistive touch screen.
- The touch screen can be activated with any object (finger, gloved hand, stylus, pen, and many others),
- It comes at the lowest cost among other touch screen technologies,
- It’s resistant to surface contaminants and liquids such as oil, grease, dust, or moisture,
- It offers a tactile feel,
- Low power consumption.
- The resistive touch screen offers lower image clarity compared to other touch screen technologies,
- The outer polyester film can be damaged (for example, through scratching or poking with sharp objects).
2. Surface capacitive touch screen
One of the most popular types of touch technologies on the market today, a surface capacitive touch screen monitor includes a transparent electrode layer located on top of a glass panel. All of that is then placed in a protective cover.
When a user touches the monitor screen with their finger, the screen will react to the static electrical capacity of the human body. Some of this electrical charge is then transferred from the screen to the user. Sensors located at the four corners of the screen identify the decrease in capacitance. This is when they allow the controller to determine the touchpoint.
Note that surface capacitive touch screens can be activated only when touched by human skin or a special stylus that holds an electrical charge. This type of touch technology is commonly used in industrial environments.
- This type of touch screen offers higher image clarity than the resistive touch screen,
- It has high durability,
- It offers outstanding resistance to liquids and surface contaminants such as grease, oil, dust, or water droplets,
- It comes with high scratch resistance.
- The screen requires a bare human finger or capacitive stylus/glove for activation,
- It has a sensitivity to EMI/RFI.
3. Projected capacitive touch screen
A projected capacitive (P-Cap) touch screen offers two advantages over the surface capacitive touch screen. It can be activated by a bare finger, but also surgical gloves or thin cotton gloves. It also enables multi-touch activation – for example, two or more fingers together.
How does P-Cap work? The touch screen includes a sheet of glass into which are embedded transparent electrode films and an IC chip. Thanks to this, we get a 3D electrostatic field. When the user touches the screen, the ratios of electrical currents change immediately and the device can easily detect the touchpoint.
- This type of touch screen offers excellent image clarity,
- It’s more resistant to scratching than the resistive touch screen,
- It also offers good resistance to liquids and surface contaminants such as oil, grease, dust or moisture,
- It offers multi-touch functionality with two or more touchpoints at the same time.
- This type of touch screen is sensitive to EMI/RFI,
- It can only be activated using a bare finger, or thin surgical/cotton gloves.
4. SAW (Surface Acoustic Wave) touch screen
A SAW touch screen monitor uses a set of piezoelectric transducers and receivers, which are located along the sides of the glass plate. That way, they create an invisible grid of ultrasonic waves right on the monitor’s surface. When the user touches the screen, some of that wave is absorbed. This is how the receiving transducer can locate the touchpoint and then send this data to the device.
Note that SAW monitors can be activated with an exposed finger, but also a gloved hand or soft-tip stylus. In comparison to other types of touch screens SAW also offers excellent clarity, durability, and resolution.
- This type of touch screen comes with outstanding image clarity and resolution,
- It provides excellent scratch resistance (better than surface or projected capacitive touch screens),
- It has a high “touch-life”.
- This screen can’t activate with hard items such as pens, credit cards, or fingernails,
- Water droplets on the screen surface may cause false triggering,
- If the screen is covered in solid contaminants, they might create non-touch areas until their removal.
5. IR (Infrared) touch screen
An IR touch screen monitor doesn’t overlay the display with an extra screen or screen sandwich. Instead, it uses IR emitters and receivers to create a grid of light beams across the screen, which is invisible to the human eye. This is how it offers an incomparable image quality.
How does an IR touch screen work? When an object interrupts the infrared light beam, the sensors can locate the touchpoint and send the X and Y coordinates to the controller.
This type of touch screen is often used in outdoor locations. Moreover, IR touch screens offer excellent durability and can detect any type of input.
- This type of touch screen comes with the highest image clarity and light transmission, compared to all of the other touch technologies on the market,
- It provides an unlimited “touch-life”,
- It’s resistant to surface scratches,
- It offers multi-touch functionality, allowing two or more touchpoints,
- It has a Palm Rejection Capability.
- It’s easy to accidentally activate the screen since the infrared beams are located above the glass surface,
- The buildup of dust, oil, or grease on the screen (or even the frame) might prevent light beams to work as they should,
- Snow buildup or pooling of water might cause false triggering,
- This type of screen is often sensitive to direct high ambient light interference,
- This technology is very expensive.
We hope that our overview of each touch screen monitor technology helps you to decide which one is the best match for your application’s needs.If you’d like some more advice, please get in touch with our experts. We realized many applications in the strictest industries such as medical or defense, providing our clients with touch screens that were perfectly suited to their unique requirements.
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