Projected capacitive vs resistive touch screens: What’s right for your project?

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Selecting the most suitable type of touch screen for your project can improve device functionality and durability, which can mean a significant increase in customer adoption.

How can you choose which touch screen option best aligns with your needs?

This article highlights the unique advantages and drawbacks of common touch screen technology, to help product design engineers make an informed decision.

What is a resistive touch screen?

Resistive touch is a legacy form of touch screen technology that was broadly popular for many years, but has been replaced by capacitive touch for many applications. Currently, resistive touch has a smaller range of common uses, but can still capably address certain needs.

How do resistive touch screens work?

The core elements of a resistive touch screen are two substrate layers, separated by a gap filled with either air or an inert gas. A flexible film-based substrate is always used for the top layer, while the bottom layers substrate can be either film or glass. A conductive material is applied to the inner-facing sides of the substrate layers, across from the air gap.

The resistive touch screen has only two states of operation: touched and not touched.

When a user applies pressure to the top surface, the film indents and causes the conductive material on the top layer to make an electrical contact with the conductive surface of the bottom layer. This activity creates a difference in voltage that the system registers as a touch. The location of this contact is pinpointed on the X and Y axes, and the touch controller then interprets the action. Because physical force is needed for a resistive touch screen to function, it is similar to a mechanical switch.

Resistive touch screens must be calibrated before they are used to ensure accurate and reliable operation. A user must apply pressure to the four corners of the screen, and sometimes on its center, to calibrate the screen with the rest of the system via a lookup database.

Advantages of resistive touch screens

Because resistive touch screens interpret physical pressure as a touch, they are effective in a variety of environments using single touch. Any object capable of applying force to the screen can be used with the same result. For example, in applications where end users wear gloves, resistive touch screens offer reliable single-touch functionality.

Since resistive touch screens area actuated via mechanical force, they continue to function as intended even when liquids or debris are present on the surface. This makes them especially useful in situations where substances could disrupt the function of other types of touch screens. For example, on single-touch applications within agricultural equipment, boats and underwater machinery.

Besides the functional advantages of resistive touch screens, price is a common reason why OEMs select this option. In projects where cost is a top concern, companies can use this option to realize savings that may not be possible with alternatives.

Disadvantages of resistive touch screens

The configuration of a resistive touch screen removes the possibility of gestures, such as pinching and zooming, or any actions requiring multi-touch functionality. These screens cannot determine the location of a touch if more than one input is present.

In terms of visibility, the film substrate commonly used as the top surface in resistive touch screens is less transmissive than glass. This leads to reduced brightness and a certain level of haze compared to touch screens with a top layer of glass. The film layer can also expand or contract based on temperature, which alters the distance between the two layers and affects touch accuracy. Additionally, the film substrates are susceptible to scratches and can start to wear away with repeated use, necessitating occasional recalibration or replacement over time.

What is a capacitive touch screen?

Capacitive touch screens were invented before resistive touch screens. However, early iterations of this technology were prone to sensing false touches and creating noise that interfered with other nearby electronics. Due to these limitations, resistive touch screens and other options, like infrared touch screens, dominated the industry.

With more development and refinement of controller ICs, projected capacitive (PCAP) touch screens became the preferred touch technology for a majority of applications. For example, this technology is now commonly used on tablets, laptops and smartphones. Though PCAP stands for “projected capacitive (PCAP) touch”, it’s more commonly referred to as “capacitive touch”.

How do PCAP touch screens work?

The foundation of PCAP touch screens is an array of conductors that create an electromagnetic field. As a user touches a PCAP screen, the conductive finger or object pulls or adds charge to that field, changing its strength. A touch controller measures the location of this change and then instructs the system to take a certain action, depending on the type of input received.

For a device with PCAP touch technology to acknowledge an input, users simply need to touch the screen. No physical pressure is required, unlike resistive touch screens.

Another key difference from resistive touch technology is that PCAP screens can accommodate a variety of inputs, with different gestures and more contact points instructing the system to take a variety of actions. PCAP touch can support multi-touch functionality, swipes, pinches, and zoom gestures which aren’t possible with resistive touch screens.

A PCAP touch screen is very similar to a solid state switch, as its mechanism of action requires a change in the electrical field over a control point. 

Advantages of PCAP touch screens

The value that comes with recognizing multiple inputs is a clear and positive differentiator for PCAP touch screens. Users can initiate a variety of commands, providing more functionality in devices where this technology is used. Consider how consumers now expect smartphones, tablets, and interactive laptop screens to support actions requiring two fingers, like pinching and zooming. In more specialized settings, such as multi-player gaming applications, PCAP touch screens can support more than 10 inputs at a single time.

PCAP touch screens do not require initial calibration, offering a simpler experience than resistive touch screens. Additionally, PCAP touch screens are highly accurate even as they support a variety of gestures and subsequent actions by the system.

Since their top layer is usually made of glass, PCAP touch screens offer a high degree of optical transmission and avoid the appearance of haze to users. Additionally, the glass top layer provides improved durability compared to the film top layer of resistive touch screens – even for the largest sizes of up to 80 inches (and growing).

Operation in environments where a PCAP screen may be exposed to liquids or moisture — including conductive liquids like salt water — is possible through specialized controller algorithms and tuning. PCAP technology has evolved to support medical glove and thick industrial glove operation, as well as passive stylus operation.

PCAP touch screens can be customized with different cover lens materials (soda lime, super glasses, PMMA) based on application specific needs. Cover lenses can be ruggedized with chemical strengthening and substrates that improve impact resistance. This can be especially valuable for public-facing applications, like ATMs, gas pump displays, and industrial applications. Specialized films or coatings – such as AG (anti-glare), AR (anti-reflective), AF (anti-fingerprint) – can be added to the cover lens substrate to improve optical performance.

Disadvantages of PCAP touch screens

Unlike resistive touch screens, PCAP touch screens depend on variations in an electrical field to operate. While a passive stylus can activate this screen, a non-conductive tool like a pencil can’t.

If cost is a top concern for a project, PCAP may not align with budget limits. It is a more expensive technology than resistive screens, although it continues to grow more accessible in terms of price as the technology advances and improves.

Moving forward with your touch screen project

Summary: PCAP vs. resistive touch (comparison table)

The below table compares the advantages and disadvantages of projected capacitive touch vs resistive touch screens.

CharacteristicsPCAP TouchResistive TouchRequires calibration

No

Yes

Single-touch

Yes

Yes

Multi-touch

Yes

No

Passive stylus & glove operation

Yes

Yes

Operation with non-conductive object such as a pencil

No

Link to Touch-ChinaRelated articles:
Touchscreen

Yes

Moisture immunity

Yes

Yes

Optical Transmittance

High

Hazy

Durability

High

Low

Cost

$$$

$

Working with New Vision Display

As a leading manufacturer of touch and display products, New Vision Display can help you determine the specific needs of your project and tune your PCAP touchscreen controllers to meet them. Our PRECI-Touch® products are based primarily on PCAP touch technology and can be customized for a variety of applications using a wide range of materials, stacks, and controllers.

Whether your product will be used in a life-saving medical device, the center console of an automobile, or the navigation controls on a yacht – we can deliver an effective solution for your application. To get started on your project, contact our specialists today.

The Technology Behind Your Touch: Resistive vs. Capacitive Touchscreen

What Is a Resistive Touchscreen?

A resistive touchscreen is a device that operates based on pressure applied to the screen, making it versatile and functional across a range of conditions. This technology is often hailed for its durability and versatility, especially in industrial applications. But what exactly makes a resistive touchscreen work? Let's break it down to its core components and functionalities.

Layers Involved

A resistive touchscreen is composed of two primary layers: a flexible outer layer of plastic and a rigid inner layer of glass. These layers are coated with a conductive material. The two conductive coatings face each other, separated by a thin gap filled with insulating spacers, usually in the form of microscopic dots. This arrangement ensures that the two conductive surfaces do not touch under normal conditions.

The Mechanism of Pressure-Based Touch Detection

When pressure is applied to a resistive touchscreen — whether through a finger, stylus, pen, or other object — the flexible outer layer deforms slightly and makes contact with the inner layer. This creates a closed electrical circuit at the point of touch. The touch controller then measures the electrical resistance at this specific point to calculate the X and Y coordinates of the touch event. This data is subsequently translated into a command or action that the underlying system or application understands.

Touch Resolution and Accuracy

In terms of touch resolution, a resistive touchscreen can offer decent accuracy, especially when calibrated correctly. However, it typically does not provide the same level of pinpoint accuracy as a capacitive touchscreen. This is partly because the multiple layers involved in resistive technology can diminish visual clarity, and the pressure-based mechanism can sometimes introduce minor errors in touch detection. Nonetheless, a resistive touchscreen's accuracy is more than adequate for many industrial applications.

Resistive Touchscreen Advantages

Now that we've explored the operation of a resistive touchscreen, it's time to discuss why it might be the ideal choice for certain industrial applications. Resistive touchscreens have unique advantages that make them particularly well-suited for challenging environments and specific use cases.

Lower Cost

One of the most compelling advantages of a resistive touchscreen is its cost-effectiveness. A resistive screen is generally less expensive to manufacture than a capacitive touchscreen. This makes resistive touchscreens an attractive option for budget-conscious projects or for situations where a large number of screens are needed, such as in manufacturing lines or control systems requiring multiple interface points.

Operable with Gloves, Stylus, or Other Objects

Unlike a capacitive touchscreen, which relies on the electrical properties of the human skin to detect touch, a resistive touchscreen works based on pressure. This means they can be operated using a wide range of objects like a gloved finger, a stylus, or even a pen. This versatility is particularly useful in industrial settings where operators may wear protective gloves.

Durability in Harsh Environments

Another significant advantage of resistive touchscreens is their resilience in challenging conditions. The technology is generally more robust regarding exposure to elements like water and dust. The pressure-based touch detection mechanism means that the screen can still function even when dirty or wet, which would often impair the functionality of capacitive touchscreens. In industrial settings, where machinery may be exposed to dust, moisture, or chemicals, a resistive touchscreen's durability can be critical in maintaining uninterrupted operations.

Resistive Touchscreen Disadvantages

While a resistive touchscreen offers a range of advantages, particularly in industrial settings, it does have drawbacks. Understanding these limitations is crucial for making an informed decision that aligns with your specific operational needs.

Lower Sensitivity

A resistive touchscreen requires physical pressure to register a touch, which inherently makes it less sensitive than a capacitive touchscreen that senses the electrical charge from a human finger. The need for pressure means that quick or light touches might not be registered, possibly affecting the speed and efficiency of specific interactions. This lower sensitivity can be a drawback in applications requiring fast, accurate responses.

Limited Multi-Touch Capabilities

Another limitation of a resistive touchscreen is its inability to support advanced multi-touch gestures, like pinching or zooming, which are easily handled by capacitive screens. Multi-touch support would require additional layers and more complex circuitry, making it cost-prohibitive in most resistive models. In industrial contexts, this means that a resistive touchscreen is often best suited for simple, straightforward interactions rather than complex multi-touch gestures.

Reduced Visual Clarity Due to Multiple Layers

A resistive touchscreen consists of multiple layers, including an insulating layer that separates two conductive layers. This multi-layer structure can reduce visual clarity by diffusing the light emitted from the screen. While this may be a minor concern for some industrial applications, it could be a drawback for tasks that require high-definition visuals or intricate details, such as detailed monitoring or data visualization.

Resistive Touchscreen Applications

Despite its limitations, a resistive touchscreen is often the technology of choice in various industrial scenarios, thanks to its unique blend of durability, cost-effectiveness, and versatility.

Industrial control systems often operate in environments that can be harsh, with varying levels of moisture, temperature, and contaminants like dust or oils. The robustness of resistive touchscreens, coupled with their compatibility with gloved operation, make them a favored choice for control panels and automated assembly lines.

Manufacturing facilities are often characterized by conditions that could be considered hostile to delicate electronics — exposure to chemicals, constant vibrations, and potential impact risks are common. In such settings, the durability of a resistive touchscreen becomes a significant advantage. Its relatively simple construction and lower sensitivity to environmental factors mean it can provide reliable performance where other types of screens might fail.

What Is a Capacitive Touchscreen?

A capacitive touchscreen is a device that provides a touch experience based on electrical conductivity rather than pressure. These screens are rapidly becoming the standard in many consumer devices like smartphones and tablets, but their utility also extends into the industrial sector. Let's look at the technology behind capacitive touchscreens to understand what sets them apart.

Layers and Electrical Properties Involved

Unlike a resistive touchscreen, which is built from multiple layers, a capacitive touchscreen typically consists of a glass panel coated with a transparent conductor, usually indium tin oxide. This conductive layer stores an electrical charge. On top of the glass layer, there might be a protective layer to guard against scratches and other physical damages, but it's not involved in the touch-detecting mechanism.

Mechanism of Touch Detection via Electrical Fields

When a user touches a capacitive touchscreen, the screen's electrical properties change at the point of contact. Here's how it works: The conductive coating creates an electrostatic field — essentially a uniform electric field generated by stored charges. When a finger, which is also electrically conductive, comes into contact with the screen, it alters this electrostatic field. By disrupting the field, the finger draws a small amount of electrical current at the point of contact.

The screen's touch controller can detect this change in electrical properties and calculate the precise location of the touch event. The data is then translated into specific coordinates, allowing the underlying software to interpret the touch and initiate the appropriate response or action.

Capacitive Touchscreen Advantages

A capacitive touchscreen offers distinct advantages that cater to specific needs and applications, some of which can be particularly beneficial in industrial settings.

High Sensitivity and Responsiveness

One of the most obvious advantages of a capacitive touchscreen is its high sensitivity and responsiveness. Unlike resistive screens that rely on pressure, capacitive screens detect touch through electrical fields. This allows for instantaneous and highly accurate touch recognition. The sensitivity enables quicker data input and navigation, a boon for tasks that demand speed and precision. This is especially beneficial in control rooms or monitoring stations where rapid response is crucial.

Better Visual Clarity

A capacitive touchscreen generally offers better visual clarity than a resistive model. The simpler layer structure and absence of a separate resistive layer mean more light passes through, providing brighter and sharper images. This enhanced visual quality is essential in applications requiring detailed graphics or high-definition data visualization, such as intricate machine monitoring or CAD (computer-aided design) systems in industrial applications.

Multi-Touch Capabilities

Perhaps one of the most defining features of a capacitive touchscreen is its ability to support multi-touch gestures. Whether it's pinching to zoom or using multiple fingers to navigate different controls simultaneously, capacitive technology makes it possible. Multi-touch support can dramatically improve the user interface experience, allowing for more complex and intuitive interactions. This is particularly useful in advanced control systems where operators may need to manipulate multiple variables at once.

Capacitive Touchscreen Disadvantages

While it has several noteworthy advantages, a capacitive touchscreen also has limitations that may be deal-breakers in specific industrial contexts.

Generally More Expensive

Cost is often a significant consideration in any industrial project, and capacitive touchscreens generally come at a higher price than resistive screens. The technology involves more complex circuitry and materials, such as indium tin oxide, contributing to the cost. This factor alone could tip the scales in favor of resistive screens for large-scale deployments or budget-conscious projects.

Inoperable with Most Gloves or Non-Conductive Stylus

One of the limitations of a capacitive touchscreen is its inability to recognize touch through most types of gloves or non-conductive objects. Since the technology relies on the electrical conductivity of the human skin, using standard gloves or a plastic stylus won't work. This can be a significant hindrance in industrial settings where operators must wear protective gloves or a stylus is preferred for precision tasks.

Vulnerability to EMI (Electromagnetic Interference)

Capacitive touchscreens are more sensitive to electromagnetic interference (EMI) than resistive screens. Industrial environments often contain multiple sources of EMI, including large motors, transformers, and other heavy machinery. The presence of strong electromagnetic fields can interfere with the functionality of a capacitive touchscreen, potentially leading to erratic behavior or reduced accuracy.

Capacitive Touchscreen Applications

Capacitive screens are not just for consumer gadgets; they also find purpose in specific industrial and specialized settings. A capacitive touchscreen offers compelling advantages for high-precision control systems. Capacitive touchscreens stand out for their high sensitivity and responsiveness, making them ideal for systems that demand high-precision controls. Whether it's fine-tuning parameters on a PLC (programmable logic controller) or managing sophisticated robotics, the superior touch accuracy of capacitive screens can be invaluable. Capacitive screens often outperform their resistive counterparts when precise input and fast response times are critical.

In settings that require strict cleanliness, such as pharmaceutical production lines, a capacitive touchscreen offers a key advantage. Their glass surface is easier to clean and sanitize than the plastic overlays on resistive screens. This makes them more suitable for applications where hygiene is a priority, and they can more readily comply with industry-specific cleanliness standards.

The multi-touch capabilities of a capacitive screen allow for a more dynamic and versatile user interface. This is especially beneficial in complex systems where multiple data points need to be manipulated simultaneously or where intuitive gesture controls can make operations more efficient. For instance, zooming into a detailed data visualization chart during a quality inspection or using multi-finger gestures to control various aspects of a machine in real time can be accomplished effortlessly with capacitive technology.

Resistive vs. Capacitive Touchscreen: How to Decide

We've looked at the resistive vs. capacitive touchscreen question from several angles. But how do you decide which technology is the right fit for your specific industrial application? To guide you through this critical decision-making process, here are some key factors to consider:

Budget

Cost considerations are often at the forefront of any industrial project. A resistive touchscreen usually comes at a lower price point due to simpler technology and materials. On the other hand, a capacitive touchscreen, with its advanced features, generally costs more. It's crucial to weigh the benefits against the costs to determine which technology offers the best value for your needs.

Environmental Conditions

The operational environment can significantly impact the performance and longevity of touchscreen devices. If your application is in a harsh setting — exposed to water, dust, or extreme temperatures — a resistive touchscreen could be the more durable and reliable choice. Conversely, if the environment is relatively clean and controlled, a capacitive touchscreen's superior visual and touch experience might be more appropriate.

Required Touch Sensitivity and Multi-Touch Capabilities

The level of touch sensitivity required for your application can be a deciding factor. A capacitive touchscreen excels in providing high sensitivity and support for multi-touch gestures, which can be indispensable for complex control systems. While generally less sensitive, a resistive touchscreen is more versatile in that it can be operated with gloves, a stylus, or other objects — features that may be critical for your application.

Durability

While both screens can be rugged for industrial use, their inherent construction gives them different durability profiles. A resistive touchscreen is generally more resistant to harsh conditions like exposure to liquids or dust, making it well-suited for challenging environments. Although easier to clean and sanitize, a capacitive touchscreen is more susceptible to issues like electromagnetic interference.

Frequently Asked Questions About Resistive and Capacitive Touchscreens

As a leading supplier of industrial automation parts, we're well-suited to answer your questions about resistive and capacitive touchscreens. Read the following to learn more information.

Which Is Better: Resistive or Capacitive Touchscreen?

A resistive touchscreen is better for applications in harsh environments, while a capacitive touchscreen is best for applications needing multi-touch capabilities.

What Are the Disadvantages of a Resistive Touchscreen?

The disadvantages of a resistive touchscreen include its lower sensitivity, limited multi-touch capabilities, and reduced visual clarity.

Why Are Resistive Touchscreens Used?

Resistive touchscreens are used when cost and harsh conditions are a concern.

Trust Your Industrial Replacement Part Needs to Industrial Automation Co.

Now that we've thoroughly explored the question of resistive vs. capacitive touchscreen, you're ready for the next step. Industrial Automation Co. is a trusted source of industrial replacement parts. We understand our customers' needs and provide a broad range of HMIs designed for specific applications. We also offer unparalleled customer service and outstanding turnaround time, ensuring you get the components you need when you need them. Shop now and experience the Industrial Automation Co. difference.

If you want to learn more, please visit our website 24 Inches Resistive Touch Screen.

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