Resistive or capacitive - what is the right touch panel?

We all use touchscreens every day. Touch panels are so common, that we don’t notice them anymore. Think about all the times when you use touch panels: typing out a text message, getting cash from an ATM, and adjusting the temperature in the office.

You might be aware of the differences between particular touch panel modules. Touch panels vary in response time, required pressure or different texture under your fingers.

Each type of touch panel responds differently because of the underlying technology.

You want to choose the best type of touchscreen for the project you’re working on? Try to decide based on what environment and what circumstances the display will be used in.

The three main touch screen components are:

•        Touch sensor
•        Controller
•        Software driver

Our shop gives you two versions to choose from: capacitive and resistive touch panels.

Table of Contents

• The resistive touch panel
• The capacitive touch panel
  • Surface capacitive
  • Projected capacitive
  • Conclusion

The resistive touch panel

Let’s start with resistive touch panels.

The history of resistive touch panels starts in the 1970s. For years, that was the most common touch input technology. But it wasn’t just the number of years the resistive touch panels had over capacitive ones. Resistive touch panel technology is cheaper than the capacitive touch screen components.

According to the technology name, the resistance measurement is what detects the touch. The pressure on the screen of the touch panel translates directly to change in the Ohm value.

A resistive touch panel has several layers:

The conductive layers of ITO or Indium Tin Oxide (see the image above) are separated by spacer dots. That prevents them from touching one another while the touch panel is not in use. What happens when a finger touches the touch panel? This space between spacer dots disappears and the layers detect the resistance change. Then the coordinates of the touch are being calculated.

The main advantages of resistive touch panels are:

• Lower price
• You can use them with a gloved hand or a stylus
• Better for rugged environments

Resistive touch panel disadvantages:

• They do not respond to multi-touch
• Not as sensitive to a light touch
• Scrolling can be difficult, as the surface is not as smooth as on capacitive screens

The capacitive touch panel

Capacitive touch panel technology relies on the capacitance of the human body. Meanwhile, the resistive technology depends on pressure applied on the touch panel., and not on pressure like resistive technology. There are two types of capacitive touch panels – surface capacitive and projected capacitive.

Both touch panels work on detecting the change of capacitance on the screen.

Surface capacitive

Capacitive touch panels are more often used for big surfaces, as they need less accuracy.

Let’s see take a look at how capacitive touch screen components work.

As you probably may already know, a thin glass surface covers capacitive touch screens. Under this glass surface, covered with a protective layer, lies a thin layer of electrodes. The electrodes on the corner of the touch panel provide the voltage for the thin film layer. As your finger touches the screen a small electrical charge is transferred to the finger and the electrical circuit is complete. This creates a voltage drop on that part of the screen, and the touch is being detected.

Projected capacitive

The projected capacitive touch panel is a more complex capacitive technology. Beneath the glass with the protective cover (mentioned above), there is a pattern of electrode layers – called the matrix. This pattern forms the plane of X and Y coordinates, which the controller uses to calculate the touch event.

This variant of touch panels is used for smaller dimensions, as it’s more accurate than surface capacitance.

This is why you can’t use a capacitive touch screen when you’re wearing gloves.

Capacitive technology advantages are:

• Excellent sensitivity
• Multi-touch capability
• Very good durability with glass front designs

The disadvantages are:

• The size of the screen limits the accuracy of the sensitivity
• The price is higher than for resistive panels
• It can’t be used with gloved hands or a stylus (those require a more sophisticated driver)

Conclusion

So, next time you’re starting a project and you don’t know what type of touch screen components you should choose, check out this article. Think about what kind of environment the touch panel will be in. If you are planning to use this device in a more rugged, industrial setting, a resistive touch panels will work better. It’s because you can use this touch panel with both gloved hands and a stylus.

But if you design the device for a more sophisticated application, then a capacitive touch panel is our recommendation. With capacitive touch panels multi-touch is not a problem, you can easily scroll and have excellent sensitivity.

Which is better – Resistive or Capacitive Touch Screens?

If you are looking for a clear-cut answer to the above, sorry – it’s not that simple… (but it’s capacitive in our book). Both forms of touchscreens are good at certain things in certain environments, but maybe that doesn’t make either one better (unless it’s a capacitive screen).

You may have spotted we have a favourite among the two options, but this is only because we (and you) most likely use a capacitive touch screen daily.

Resistive and Capacitive – What’s the difference?

In simple forms, it is in the name. A resistive touchscreen uses resistance in the form of minor downward pressure on a screen. A resistive screen has two layers, a hard plastic or glass top layer and a bottom layer that conducts charge. The 2 layers are separated with spacers and when pressure is applied there is a change in charge in that location, which allows the software to recognise point of contact (touch).

A capacitive touchscreen works differently. The glass on a touchscreen is usually coated with ITO (Indium Tin Oxide), which is both transparent and conductive. Beneath the screen in 4 corners, there is usually four electrodes which maintain a voltage across the glass. When you touch the glass, sensors detect the change in voltage and can determine precise positions. Your own physical touch has altered the voltage as we are naturally conductive.

Resistive and Capacitive Touch Screens… Which is better?

We deliberately said positions as plural in last paragraph because this is where capacitive screens come into their own. Multiple touches, swipes and pinches can be detected with capacitive touch screens. Resistive screens generally can register one command at any given time.

This is why most smartphones and tablets use capacitive screens. There is an added benefit of better clarity than that of resistive screens (which utilise the two layers causing a loss of image quality on screen).

However, resistive touchscreens have their place, and we probably couldn’t live without them. Generally, they are more robust than capacitive screens which makes them ideal for use in public facing environments as well as military and medical environments.

Resistive touchscreens can also be used whilst wearing gloves. For military and medical, that can be vital. We were joking at the start of this article – capacitive screens are not better, we think both types of touchscreen are equal in terms of what they do and how they benefit the world we live in, in differing ways.

Resistive and Capacitive Touch Screens Supplier

We can provide both capacitive and resistive touch screens, from development to production volumes, and in sizes ranging up to 1m x 1m. The screens can be provided with anti-glare and other finishes as required, and produced on glass or plastic (flexible or rigid).

If you would like to know more about our touchscreens, please get in touch with us today to discuss your specific requirements.