Zytronic®, PCAP, Resistive: The Best Touch Technology for Every Industrial Application

Introduction

In industrial applications, human-machine interaction has historically occurred through buttons, keyboards, switches, and pointing devices. As electronics have become more powerful, touchscreens have replaced most physical control devices.

Today, many machines are operated via digital interfaces displayed on touch-sensitive screens.

Interface screens can be very small (the size of a smartwatch, for example) or very large (think of a panoramic dashboard for yachts).

To make these displays touch-sensitive, various technologies are currently available, each with its own advantages and disadvantages.

Technology Comparison

The most widely available touch technologies today are essentially three: resistive (RTP = Resistive Touch Panel), capacitive (PCAP or CTP = Capacitive Touch Panel), and Zytronic.

CJB has over 20 years of experience in the implementation and supply of touch screens and has worked with all of these technologies, gaining an appreciation for their differences.

Resistive Touch

Resistive touch screens consist of a double layer of plastic film placed in front of the display or its protective glass. Pressure from any finger or pointed object (but not too sharp!) is registered as a touch, as it alters the resistive properties of the membrane itself, which are detected by specially calibrated control electronics.

This technology is used for decidedly low-cost applications and where thick gloves are worn, making it suitable for very specific uses. This is because the touch membrane must be placed in front of the protective glass rather than behind it, and the membrane itself is delicate. Therefore, it cannot guarantee resistance to the stresses and abuse typical of industrial use, such as scratches, dust (like metal shavings), etc.

Additionally, the resistive touch membrane is slightly opaque, making the screen less sharp. Furthermore, it does not support multi-touch, is not resistant to high temperatures, and can be damaged by excessive pressure, overly sharp objects, aggressive cleaners, solvents, or degreasers, ice, and light external weather effects or vandalism.

In the past, CJB extensively used resistive technology until more advanced and cost-effective technologies became available on the market.

Today, CJB still provides resistive touch screens only in use cases where no other technology is ideal.

Capacitive Touch (CTP or PCAP)

Capacitive touch technology has gained immense popularity over the past 20 years. Today, it can be found on the screens of virtually all smartphones, smartwatches, tablets, multimedia panel PCs, and we are beginning to see it in control panels for ovens, refrigerators, washing machines, and consumer or industrial devices.

It consists of two layers of extremely thin metallic deposits applied directly to the protective glass of the display. This metallic grid essentially becomes a large multi-cell capacitor. The proximity of a finger or any surface that can alter the capacitance of the grid creates a charge imbalance that is registered by the touch controller and translated into touch sensitivity.

CJB extensively operates with capacitive screens and currently offers them as the preferred solution for designing touch interfaces for small machinery used indoors or under traditional operating conditions.

Among the leading manufacturers of electronics and control algorithms for capacitive touch surfaces, we can mention EETI and ILITEK. CJB boasts extensive experience in using and writing drivers for both manufacturers (as well as many others).

Capacitive touch screens have strengths and weaknesses, and they are not always the most suitable solution.

Key advantages include:

• The touch surface is made of glass, making it resistant to solvents, chemicals, water, and vibrations.
• It supports multi-touch, making the command interface more versatile.
• It is economical, especially in small and medium formats.
• It is easily calibratable and rarely requires recalibration.

However, the disadvantages make them less suitable for more demanding or specific uses:

• The glass is thin and tends to break easily if bumped or dropped.
• Poor compatibility with water droplets, humidity, and condensation.
• Inability to function underwater.
• High difficulty or impossibility of use with thick gloves.
• Challenges in implementation on large screens.
• Increased costs as the screen size increases.
• Difficulty or impossibility in achieving the "hovering" effect, meaning registering the approach or withdrawal of a finger.

In recent years, manufacturers of capacitive touch controllers have developed advanced algorithms to better tolerate humidity and water droplets, making capacitive glass screens more responsive even in the presence of thick gloves or personal protective equipment (PPE).

Where capacitive touch fails to provide adequate performance, CJB offers the more advanced Zytronic touch technology.

Zytronic Touch Technology

Zytronic is a UK-based company founded in the post-war era, originally established as a manufacturer of armored glass for military use.

Over the last 20 years, it has developed and patented proprietary technology to make high-resistance, thick glass surfaces touch-sensitive, based on an enhancement of the PCAP (Projected Capacitive) technique.

The Zytronic technology allows glass with a thickness of up to 20 millimeters to be rendered touch-sensitive while maintaining high sensitivity and tolerance to extreme stress, even in the presence of mounting inaccuracies and frame deformations caused by heavy use.

A Zytronic touch operates similarly to a capacitive touch: a virtually invisible metallic structure made up of numerous antennas is laminated onto a protective glass, generating an electromagnetic field.

When a body containing water, such as a finger, approaches, it creates an imbalance in the electromagnetic field, which is registered as a touch or, alternatively, as a simple hovering action.

Since the early days of Zytronic, CJB has been offering this technology as a valid alternative to capacitive touch systems, and today, it is one of the most experienced integrators of Zytronic technology in Italy.

Zytronic touch technology allows for the creation of touch surfaces several meters wide, as it can be laminated onto shaped glass, with custom dimensions and finishes such as glossy, matte, anti-glare, or beveled edges.

The touch sensitivity does not require the finger to make direct contact with the glass, only proximity, ensuring reliable performance even when wearing thick gloves (such as those used in factory settings, steel mills, bakeries, etc.).

The ability to calibrate the touch distance also means that touches can be registered even if the customer adds an additional protective glass in front of the touch glass.

The advantages can be summarized as follows:

• Allows for greater glass thickness, up to 20 millimeters.
• Can register touches even with very thick gloves.
• Tolerant to water splashes, rain, solvents, oils, chemicals, humidity, and condensation.
• Custom-shaped, as it consists of a metallic lamination on the glass.
• Software calibration of the touch registration distance is possible.
• Can register hovering of fingers without confusing them with a touch.
• Supports multi-touch even in the presence of disturbances such as water and humidity.

Today, Zytronic touch technology represents the crown jewel of CJB's touch offerings due to its versatility, customizability, and reliability.

If you need to integrate traditional touch technologies or Zytronic® into your industrial systems, contact us for more information.