Smartphones and tablets have made touch-enabled interfaces an integral part of our lives, with touch rapidly becoming the user interface of choice across most applications and industries.  A simple touch-based interface is no longer a key differentiating feature for high-end applications, though, and increasing competition between OEMs is driving down prices. Touchscreen systems represent one of the more expensive modules in portable applications, and they need to be designed in at a lower cost while still providing a high level of functionality.

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Most touchscreens implement either resistive or projected-capacitance touch technology. Resistive touchscreens, which allow both finger and non-finger input (e.g., glove, stylus), are used in feature phones, global positioning systems (GPS), printers, digital cameras, and larger displays. They generally support single-finger touch and basic gestures, and cost less to produce.

On the other hand, projected-capacitance touchscreens, having superior multi-touch performance, durability, and optical clarity, are usually adopted into smartphones and tablets. However, projected-capacitance touchscsreens are now displacing resistive touch in most small- and medium-sized touchscreen devices, too. Moreover, increasing innovation in projected-capacitance touch, such as integrated stack-ups, has allowed it to be more price-competitive while surpassing resistive touch in performance.

Market Value

The primary value proposition of resistive touchscreens is that they are low cost to manufacture. Although resistive-touch performance is usually limited to basic single-finger touches and gestures, it still serves a wide user base. Resistive touchscreens can be found in automotive, medical, and industrial equipment, and of course, point-of-sale (POS) terminals.

Resistive touchscreens also continue to dominate applications that require touchscreens greater than 10 inches, since costs for projected-capacitance technologies rise exponentially with screen size. Furthermore, some original equipment manufacturers (OEMs) continue to employ resistive touchscreens in feature phones, GPS, digital still cameras, and printers with the aim to keep costs low in markets experiencing severe price competition.

In contrast, projected-capacitance touchscreens offer high performance in accuracy, power consumption, and refresh rate. They also feature excellent optical transmissivity (greater than 90%), resulting in brighter, clearer displays. Unlike resistive touchscreens, projected capacitance is durable, scratch-resistant, free of aging symptoms, and needs no calibration.

Projected capacitance can also support multi-finger touch input and gestures, enabling significant improvements to the user interface. Popular gestures such as two-finger pinch and zoom let users zoom in or out on an image. With multi-touch, OEMs are able to develop custom gestures, which add value for end users and can be promoted as product differentiators.

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. 

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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

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.

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