If you’re familiar with the general mechanics of touchscreen devices — including smartphones, tablets and human machine interfaces (HMIs), you probably know that most use capacitive or resistive technology to detect touch commands. While both types of devices are popular, there are others available on the market, including infrared (IR).

Also known as IR grid touchscreens, IR touchscreens leverage the power of IR light to detect touch commands. They still function like any other touchscreen device, allowing you to control them by tapping the display with your finger or a stylus. IR touchscreens differ from their capacitive and resistive counterparts, however, by relying on the use of IR light. Specifically, there are two types of IR touchscreens, which are described below.

Type #1) IR Grid

IR grid touchscreen technology lives up to its namesake by creating a grid-like array of horizontal and vertical light-emitting diodes (LEDs). The individual LEDs are attached to the edges of the screen, but they form of a grid at the junction where the IR light intersects. IR grid touchscreens also have sensors placed along the edges that measure the IR light, allowing them to easily detect when and where a touch command occurs.

When you perform a touch command on an IR touchscreen, you’ll interrupt the flow of IR light to the respective sensor or sensors. As a result, the device can pinpoint the exact location of your touch command.

Type #2) IR Acrylic Projection

The other type of IR touchscreen technology is IR acrylic projection. It’s called “acrylic projection” because it uses a clear sheet — typically made of acrylic — as a back layer from which images are projected. Along the edges of the acrylic sheet are LEDs that, like with IR grid touchscreens, emit IR light. There are also cameras or sensors on IR acrylic projection touchscreens that measure the IR light.

When you perform a touch command on an IR acrylic projection touchscreen, IR light will leak around the area of the screen where you touch. The device will detect this leakage and register it as a touch command.

To recap, both IR grid and acrylic projection use IR light to detect touch commands. The difference is that IR grid literally creates a grid of IR light on top of the screen, whereas IR acrylic projection emits IR light from a back layer, which is typically made of acrylic. Both are highly effective and useful technologies for producing touchscreen devices.