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What Is an IR Touch Screen?

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  • Written By: Alex Newth
  • Edited By: Angela B.
  • Last Modified Date: 18 September 2016
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An infrared (IR) touch screen is a screen with which one interacts by touching the screen's surface rather than by using an input object such as a mouse, and it operates with IR light. With an IR touch screen, there are many different IR light-emitting diodes (LEDs); when a finger or object changes the light pattern, the screen picks up the touch. Unlike some other touch screens, which need a conductor such as a finger, an IR touch screen can be activated with nearly any object. The glass screen of an IR screen does not need to be patterned, so these touch screens tend to have better durability and clarity when compared to other touch screens. These touch screens are seen on cash registers, some computers and medical devices.

With an IR touch screen, there is a photodetector and an array of IR LEDs that cover the entire screen. When the user touches the screen, the touch disrupts the LEDs, and both the screen and photodetector notice this disruption. By correlating the two factors, this touch screen knows exactly where the user touched and simulates a mouse click for that area. This enables users to open files and click buttons without a mouse, which is much more useful in some applications.

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Most touch screen hardware requires a conductor such as a finger or apparatus, but the IR screen does not need this. The advantage is that anything can be used, so users do not need to purchase or maintain special equipment. If something falls or unexpectedly touches the screen, however, it will register that as a touch. This means a finger, plastic or metal stylus, pen cap or anything else can be used to operate the IR touch screen.

Many touch screen systems require glass with specialized patterns so the computer can recognize where the user is touching. An IR touch screen does not use this system, so the glass is same as with a regular screen. The advantage of this is that the glass usually lasts longer and has better optical quality. At the same time, these screens may sometimes incorrectly register a touch, because the touch interface is not as sophisticated.

IR touch screen hardware is seen most often on cash registers, some desktops and some medical devices. It also is used for some video games, but this is not very common. The reasons behind this touch screen’s wide use are low maintenance and ease of use.

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matthewc23
Post 7

@Emilski - Good question. I think the basic advantage of the infrared screen is that it is cheaper and easier to use. The can be located about anywhere, and people can use them with gloved hands or a stylus or whatever they want.

For the conductive type, though, it might be more expensive, but the screen quality is much better. The light emission is brighter, which makes it much more popular for things like cell phones or computer screens where people might be watching videos or viewing pictures.

Like someone else mentioned before, some people say that the infrared screens can be affected by bright lights, but I have never seen it happen. Would be an interesting experiment if you had access to an infrared screen.

Emilski
Post 6

@kentuckycat - I don't think the infrared sensors are actually in the screen. From what I have always read, the infrared part actually comes from a ring of sensor that surround the screen and make a sort of invisible field across the face of the glass. Whenever your finger touches part of the screen, the sensors around the edge can use the X and Y coordinates to figure out exactly where your finger is and how that corresponds to what is on the screen.

Because of all that, I don't think shining an infrared beam at the screen would do anything, since there wouldn't be a physical disruption. It would be interesting to try sometime, though.

What I am wondering is what the benefit is to having an electrically controlled screen. A lot of popular devices use them, so there must be some sort of tradeoff between the electric and IR screens.

hamje32
Post 5

@nony - The IR touch screen seems to be preferable to the stylus in most instances, I would agree. However, sometimes using the human finger as the stylus is not the best alternative in my opinion.

This would be in situations where you have a virtual keyboard on something like a PDA and you “fat finger” one of the keys with your finger.

I’ve done that quite a lot, and in those instances I much prefer to use the stylus. It’s precise and easy to maneuver.

I see the IR touch screen as being more preferable in situations where you don’t need that kind of precision. I know that some tablet computers are used in educational settings for example and kids can just point to objects on the screen or drag and drop them, and the IR touch screen would be more appropriate for those kinds of situations.

kentuckycat
Post 4

I thought it was really interesting reading about how one of these screens worked. I always wondered about them. Like the article mentions, I knew some other types of screens used either electrical currents or just pressure, but I never thought about them being able to use changes in light.

So, since it is infrared, does that mean it is using two different types of light at once? Obviously, there is some sort of visible LED that shows what we see on the screen, but does it also have infrared that you could see if you looked through a camera with an infrared sensor or something?

Along those same lines, too, what would happen if you were to shine something like a TV remote at one of the screens. Would it have any effect, or does there have to be a real touch?

nony
Post 3

@lighth0se33 – I don’t think that there are any rules for etiquette governing whether you use a stylus or a finger in those situations.

The important thing as you pointed out is whatever works most quickly. When people are waiting behind you in line they are not typically watching over your shoulder to see how you’re interacting with the touch screen, but they do want you to finish your transaction quickly.

TreeMan
Post 2

@lighth0se33 - I personally don't think there is anything wrong with it. I hit the buttons with my fingers most of the time, and so does everyone else I know. The only thing I can think of is that some people might not want to touch a screen that someone else has touched, but then again, the stylus would probably have more germs on it than the touch screen.

I have actually been to quite a few places where there isn't a stylus, and you have to use your finger, even for signing your name.

Is there anything that a normal person would have in their home that would use an infrared touch screen? I'd like to take a better look at the screen itself now that I know in general how one of them works. All I can really think of is a cell phone, but mine doesn't have a touch screen.

lighth0se33
Post 1

I know that the touch screen I use at stores after swiping my debit card responds to either a pen stylus or my finger. Sometimes, the stylus works better, though, because certain screens need to have more pressure applied to them to respond.

Generally, I use the stylus when I have to sign my name on the screen, and I use my finger to press “yes” or “no” buttons. If I already have the stylus in hand, though, I will use it to press the button areas, too.

Sometimes, I get self-conscious when using my finger if a stylus is present. I don't know whether it is considered proper etiquette to use my finger, but when I am holding a card in one hand and people are behind me, it just seems quicker. Does anyone know if cashiers think it rude to use your finger on the touch screen?

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